 Okay. Hello guys. Good afternoon. Please type in your name in the comment box. Hi Sushant. Okay. So today we are going to discuss P block elements. Okay. So, so here in this P block elements, first, we will discuss here, carbon family, carbon family. So in class 11, we have two groups which we have to discuss here in P block elements, that is boron and carbon. Right. So we are discussing carbon first, since this is a combined class with HSR students also. And for them, I have already done boron family. Okay. We are doing carbon family first and then we'll continue with boron. Okay. So they have exam also tomorrow, some lab exam they have, practical exam they have tomorrow. So once we finish carbon family if they want, they can leave also. Okay. That's why I'm discussing this carbon family first. You also have exam right? Sushant Ashutosh, RLR students. And the school is now, now it's closed, right? For preparation holiday. So Monday onwards, you have, you have exams, right? School exam. Okay. Last day for the school. So when can we have our class on Monday? Okay. Monday is chemistry. When can we have our class on Monday? Sorry, on Saturday? Yes, we'll let you know after 20 seconds, what is the schedule that I'm not sure with? Okay, we'll let you know Bharat. That's what I'm asking since I'm waiting for more of more students to join this. That's why I'm asking all these things. What do you want me to do on Saturday? Can we do some basic revision of class 11 on Saturday since you have exams? No, Bharat, we cannot take organic problem solving. We have to take care of other students also. Yes, mostly we'll finish P block today, boron family and carbon. Like I said, we will not discuss everything. You have to study and CRT. Important thing we'll discuss today. Okay. Anyway, so we'll figure it out. What we'll discuss on Saturday. We'll let you know. So today we are going to start carbon family, right? And then we'll do boron also. So you see in carbon family, these are the elements of group 14 group 14. I'm not sure with this Ashutosh. Maybe may not be. I'm not sure with this. Anyone told you this thing that we don't have class till March? Usually it happens every year. We don't conduct classes during exam. That's the thing. Right. So does anybody told you this Ashutosh? So you see group 14 and the elements of group 14 or what? The elements are carbon, then we have silicon, then germanium in the last we have lead. Yeah, that's what. Let's see. Let's see what happens. Anyways, so these are the elements of carbon family we have. Okay. So carbon is C, silicon is S, I is germanium is GE, SN and TB. Okay. Atomic number. What is the atomic number we have here? Atomic number, if we write down, that would be for carbon, it is 6. For silicon, it is 14. Then 32 plus 18, 50 plus 32 is 82. Right. So the magic number here is this difference is 8, then this difference is 18, 18 and here we have 32. So magic number of P blocks are 8, 18, 18 and 32. Okay. Electronic configuration if you draw. Right. So for the first one we can write 1S2, 2S2, 2P2 or we can also write the configuration of helium is H, helium is 1S2. So helium 2S2, 2P2. Right. Then we can write down the electronic configuration of silicon that is neon, 3S2, 3P2, argon, 4S2, 4P2, krypton, 5S2, 5P2, 5S2, 5P2. Then this is krypton, then we have in the last xenon, XE, 6S2, 6P2. Right. One thing important here again, you have to understand this, that in germanium what happens before this 4S, we have completely filled 3D orbital, 3D10. Right. Similarly in 10, before this 5S, we have completely filled 4D orbital, 4D10. Similarly in lead, before this 6S, we have completely filled 4F orbital and 5D orbital, 4S and 5D10. And we know that this DNF orbital, DNF orbital shows weak screening effect. So this thing we will use later on in this chapter to explain the trends, weak screening effect. So these are the electronic configurations. Now you see few trends if I discuss like few general thing if I tell you. Right. Carbon, like from this electronic configuration, one thing is clear that general electronic configuration if I ask you for carbon family, it will be NS2, NP2. Right. N is the number of period, NS2, NP2. For the carbon it is 2S2, 2P2 since it is in the second period, silicon 3S3, 3P2, third period, 4S2, 4P2, 5th, sorry, 4th, 5th and then 6th. Right. So okay. So now with this electronic configuration only, the trends if you want to discuss here, few trends that will be, first of all we will discuss oxidation state, oxidation state. So in oxidation state what happens? The carbon and silicon. Okay. Carbon and silicon shows plus 4 oxidation state generally, plus 4 oxidation state. Okay. But the other three elements which is germanium, tin and lead, they shows plus 4 and plus 2 oxidation state. Okay. So for germanium and tin, these three, these three element shows plus 4 and plus 2, both oxidation state, but for carbon and silicon it shows only plus 4. Right. What happens here actually you see there is a term called inert pair effect. You know what is inert pair effect? What is inert pair effect? Do you know that? Tell me. What S orbital? All these S orbital, this S orbital also, this S orbital also and this also. See that is not the thing and this is important for a school exam also. They ask you this, what is inert pair effect? See first of all if I ask you what is the order of shielding effect of orbitals? Okay. So shielding effect for orbitals. It is maximum for S, then P, then D and then F. Right. And usually we say what DNF orbital shows weak screening effect or shielding effect. I have written here weak effect DNF orbital. So when the electrons present beyond this DNF orbital, then those electrons are strongly attracted towards the nucleus since because of weak shielding effect of DNF orbital. Okay. So what happens here you see how this plus 4 oxidation state forms or get when these 4 electrons which is present in the outermost electronic shell takes part in the bonding. Okay. Takes part in the bonding. So these 4 electrons when it loses then only it forms plus 4 oxidation state and when only these 2 electrons take part in the reaction that gives you plus 2 oxidation state of the element. Right. So these oxidation state plus 4 and plus 2 depends on how many electrons present in the outermost shell takes part in the bonding. Correct. So here you see what happens. That's why I have written 3D10, 4D10 and this here. What happens when you go from silicon to zermanium since we do not have D orbital present here or here, we don't have D orbital present. Right. So what happens these electrons, these electrons and the inner orbital of these electrons or what we have S here and here we have SP both. The inner shell orbital, this is the outer shell. Right. The inner shell orbital we have 1S2, 2S2, 2P6. Here it is only 1S2. Right. So here we have SNP orbital. Here we have only S orbital but both SNP orbital shows a strong shielding effect. Right. That's why what happens these 4 electrons present in carbon and silicon. Right. Is weakly bonded to the nucleus because of strong shielding effect of SNP orbital here. Since these 4 electrons are weakly bonded, bonded so these two may take part in the reaction and that's why the carbon and silicon shows plus 4 oxidation state. Is it clear? Clear yes or no. Tell me. Clear understood. Right. So now next what happens, so this is one thing. Why carbon and silicon shows plus 4 oxidation state. Now coming back to the zermanium tin and lead, what happens when this electron goes into 4S and 4P orbital. So before going into these orbital, electron has to fill this 3D orbital here. So the penultimate shell or the inner shell here we have is nothing but the 4D orbital. Right. So the penultimate shell contains completely filled D orbital which shows weak shielding effect. So because of the weak shielding effect of D orbital, these outermost electrons which is 5S2 and 5P2 is strongly attracted towards the nucleus and this is true in the case of zermanium also tin and lead because we have 3D, 4D, 4F, 5D. Right. So because of the completely filled D and F orbital here, these electrons which is SNP, 2 electrons in S, 2 electron in P are strongly attracted towards the nucleus and this attraction is more dominating over this S orbital than this P orbital. Because why this orbital is closer to the nucleus in comparison to this P orbital. Right. So what we can say is in the case of zermanium, tin and lead, these two electrons which is present in these two electrons which is present in P sub-shell P orbital here, these electrons and these electrons. When these electrons donates, it forms plus 2 oxidation state and plus 2 oxidation state here. But comparatively, electron present in S orbital are strongly attracted towards the nucleus. That is why it is very difficult for these elements to lose electrons present in S orbital and hence they have difficulty in the formation of plus 4 oxidation state. Is it clear? Both electrons in SNP orbital is strongly attracted towards the nucleus as compared to the electrons in carbon and silicon. But when you compare the electrons of SNP orbital as will be more tightly bonded to nucleus than the P electrons. So what happens because of this D and F orbital that 2 electrons present in S orbital or in other words we can say a pair of electron present in S orbital is become inert towards the bonding. Correct. Because of weak shielding effect of D and F orbital, so a pair of electron which is present in S orbital becomes inert towards bonding. Hence we call it as what? Inert pair effect. Understood? Clear? Yes, tell me. Understood? Yeah, I'll just first try to understand what I'm saying. Definition I'll give you. Right? So what happens here? What happens here? The pair of electron becomes inert towards the bonding and hence we are calling it as inert pair effect. Why it happens? Because of completely filled D and F orbital present in the penultimate shell. Okay? This is what inert pair effect is. Now definition if you want to write down, write down here. Definition. Inert pair effect. Definition you write down. It is the it is the reluctance of NS2 electron. It is the reluctance of NS2 electrons, reluctance of NS2 electron to unpair and participate in chemical bond formation. It is the reluctance of reluctance of NS2 electrons to unpair and participate in chemical bond formation comma which arises due to which arises due to the presence of arises due to the presence of weak shielding, weak shielding, fully filled D or F electrons, fully filled D or F orbital you write down. Fully filled D or F orbitals between between the valence electron, the valence electron and the noble gas core, the noble gas core, C-O-R-E. Right? These are noble gas. So valence electron is S262 and these are D and F orbital fully filled. So what happens you see here? This is important now. As we go down the group from down the group from germanium, what happens the tendency to form plus 2 oxidation state increases right down here. Tendency to form, tendency to form plus 2 oxidation state increases. Tendency to form plus 4 oxidation state decreases. So what we can say one thing is here you write down next slide I use stability order write down stability order in this only. For plus 4 oxidation state the stability is this it is most stable in germanium then Sn plus 4 and then Pb plus 4 because plus 4 oxidation state increases down the tendency to form right but for plus 2 the stability is reverse g e plus 2 is minimum then Sn plus 2 and then Pb plus 2. This is the stability order of the two oxidation state we have okay. Now you tell me one thing here for germanium you see germanium is more stable in plus 4 oxidation state right. So whenever you have g e plus 2 it has tendency to convert into g e plus 4 right. Similarly lead is more stable in plus 2 oxidation state. So whenever you have lead Pb plus 4 it has tendency to convert into I'll write down this sign it has tendency to convert into Pb plus 2. So what is this behavior and what is this behavior tell me what is the first one and what is the second one what kind of behavior is this oxidation and reduction this part oxidation number is increasing so what happens germanium is getting oxidized is getting oxidized right means here it is behaving as a reducing agent listen to me carefully here don't get confused reducing agent right and this is what lead Pb is getting reduced right so we call it as what getting reduced so it is an oxidizing agent oxidizing agent okay. So if I write down here tendency to behave as a reducing agent tendency to behave as reducing agent right will be more for germanium than Sn and then Pb here I will write down tendency to behave as oxidizing agent is minimum for germanium then we have 10 in and then we have lead so Pb plus 4 you can say it is strongest oxidizing agent oxidizing agent here and this one is the strongest reducing agent this one sorry this one is the strongest reducing agent this property is very important okay you must remember so when you write down PbCl2 PbCl4 it always has tendency to convert into PbCl2 because here the oxidation state is plus 4 and here it is plus 2 and we know lead in plus 2 oxidation state is more stable that's why the answer will be this so if I write down here the last thing like for all the elements we have carbon silicon germanium tin and then lead carbon shows only plus 4 oxidation state silicon can show plus 2 plus 4 but generally it is plus 4 only germanium can show plus 2 plus 4 tin can show plus 2 plus 4 and lead will show generally plus 2 so in all these oxidation state this is only possible oxidation state for carbon for silicon plus 4 is the most common for germanium plus 2 is the most common then tin we have plus 2 and then for lead we have plus 2 plus 2 no germanium can have plus 4 also both oxidation state for germanium is common but this is the important part which you have to memorize as far as the oxidation state is concerned understood okay okay next write down what about the covalent radius the trend of covalent radius and red eye so that's the same thing as we go down the group as we go down the group it increases because you are adding an extra cell of extra energy shell into it so carbon will have minimum right what is the order here we get so write down the statement here first then we'll see first write down the statement in this group in this group there is considerable increase in this group covalent radius write down the statement in this group there is a considerable increase in the covalent radius from carbon to silicon thereafter from silicon to lead and thereafter from silicon to red there is a small increase in radius is observed sorry silicon to lead a small increase in radius is observed a small increase in radius is observed this is the statement for covalent radius from carbon to silicon first of all down the group it increases okay but from carbon to silicon the increase is much larger than from silicon to lead whatever the increase we have okay now the reason for this word this is due to the addition of a new shell in each each succeeding element that we already know the increase in radius from silicon to lead is a small why because of the ineffective shielding of valence shell of electron that also we have discussed since we have as we are going down the group the electrons are going into d and f orbital which has weak skinning effect and hence they appear strong attraction towards the nucleus and hence the increase in size decreases comparatively understood see gargi electronegativity is the relative concept okay we always define electronegativity in a bonding state you see what happens if you write rcl correct rcl here we say because of electronegativity here we have partial negative partial positive charge right but when you have an atom chlorine in this free state for an atom we cannot define electronegativity it is not possible because electronegativity is what it is a compare it is a relative concept it is not absolute right carbon when attached with chlorine right so here the carbon having positive charge when carbon is attached with right hydrogen in that case carbon has slightly more electronegativity so carbon will have then slightly negative charge over there so it means what this electronegativity is a relative concept it won't it we can already explain electronegativity between the two atoms for an atom which is independent free we cannot define electronegativity understood clear yes electronegativity we can only explain in bonding state to what element it is bonded with right so here the point we are talking about the covalent red eye of an element so electronegativity does not have any effect okay so the reason is same extra shell of electron we are adding and then as we are moving down the growth electron is going into dnf orbital which shows the weak screening effect so there will be a little bit of contraction in the size hence the increase in covalent red eye from top to bottom decreases right initially the increase will be more then it will be comparatively less right next right down ionization enthalpy tell me the order of ionization enthalpy increases down the group how you see the first of all write down the order of ionization enthalpy it is maximum for carbon then silicon then germanium and then lead and then tin this is the exception you can say lead has more than tin okay so first of all you write down this is the you know trend now you write down few points here first of all you write down the first ionization enthalpy of group 14 the first ionization enthalpy of group 14 so i e 1 of the elements of group 14 the first ionization enthalpy of group 14 elements are higher than are higher than that of higher than that of the corresponding elements of group 13 what is the meaning of this if you compare the first ionization enthalpy of carbon it is more than to that of boron silicon it is more than to that of aluminium this is the meaning of this point first of all okay we cannot compare you know these two or these two it it is then you know factual we have to see the energy involved here then we can say okay but this is one thing now for this order you see what happens write down as we go down the group as we go down the group the first ionization energy decreases but the first ionization energy of lead it's slightly more than to that of tin the general trend of don't write this as you listen to me the general trend of ionization energy is what as we go down the group ionization energy decreases and why it happens because the size is excuse me because the size is increasing right so size has an important role here because according to size only we have electrostatic force of attraction between the nucleus and the electron that actually defines or explains the ionization energy right so as we go down the group you see we have a factor which we call it as inert pale effect and because of inert pale effect the size starts you know the difference in size from germanium to tin is not germanium to lead is not that much high it is increasing but that that the gap is not no as high as it is in carbon and silicon correct so size is getting contracted as we go down the group that's why in case of lead the ionization energy is slightly higher than to that of tin so we have a little bit of irregularities in this order in this trend that is most important you must remember this trend understood yeah you can say that but it is an exception actually just a second yes yeah oh no no i'm not interested no i i have already so i don't require it i have already other lines so i don't require it now if you want to give me the information about the benefits and all you can call me tomorrow right i can be a bit easy okay so you can call me tomorrow 11 o'clock that would be fine okay so this is the trend we have correct so you must remember these values exceptions that we have here next to write down electronegativity write on quickly electronegativity as we go down the group electronegativity decreases right no it's not it's there is a change here a bit okay write down electronegativity first don't write down down the group it decreases so for electronegativity you see the general trend is what general trend is down the group electronegat down the group electronegativity decreases now what happens here in electronegativity write down as we go write down the electronegativity decreases from electronegativity decreases from from carbon to silicon remains constant and remains constant from slightly increases and then slightly increases from from tin to lead pb right generally what happens we say if it decreases from there's one more thing which is written in some other book decreases from carbon to silicon then after silicon onwards silicon to lead it is almost same remains same this is also written in some of the book so this also you can consider if option is like that okay these two things so there's a slight increase but that increase is not that enough okay so in some book they have written this also and some book they have written this also so any one of these you can consider according to the given option okay right again the reason is same because of the deal filling of d electrons in germanium and tin and in lead we have we have f electrons also and d electrons also that is the reason we have here okay next should write down metallic character what is the order of metallic character general trend is what as we go down the group electron enthalpy decreases metallic character increases and and what happens electro positive nature also increases right in this you write down as we go down the group as we go down the group the metallic character increases as we go down the group metallic character increases carbon here series carbon and silicon these are actually non metals germanium is metalloid tin and lead are metals soft metals these are actually metals and that is soft metal the reason behind this is what as we go down the group the effective new that we have less effective nuclear charge and the number of available orbitals also increases with increase in size of the atom okay so thing is because of less effective nuclear charge okay one more point to write down the elements of group 14 if you compare this character with group 13 and group 14 the elements of group 14 are the elements of group 14 are solids are solids and they are more electro positive and metallic and they are more electro positive and metallic as compared to the elements of group 13 they are more electro positive metallic as compared to the elements of group 13 next one write down tendency to form multiple bond tendency to form multiple bond this is again important the first type of bond you write down here which is p pi p pi bond p pi p pi so write down in this quickly carbon has a strong tendency to form p pi p pi bond carbon has a strong tendency to form p pi p pi bond with other elements of similar size this is due to other elements of similar size means what other elements of similar size means what we can have c double bond o c double bond n like this okay c triple bond n also you can write n h c triple bond n also you can write right so carbon has strong tendency to form this kind of you know p pi p pi bond with the elements of similar size this is due to the small size this is due to the small size and high electronegativity small size and high electronegativity of carbon atom next line as we go down the group as we go down the group the tendency to form p pi p pi bond decreases as we go down the group the tendency to form p pi p pi bond decreases the size increases and electronegativity decreases right so it is basically when you talk about silicon with oxygen nitrogen and all so this has you see here the thing is here we have 2p 2p orbital here also we have 2p 2p orbital all the elements here has 2p 2p orbital and that's why the lateral overlapping we have good lateral overlapping here over here but in case of silicon zermenium and all we have 3p 4p like that the orbital so overlapping of 3p and 3p and 2p orbital 4p and 2p orbital is not that possible yeah that's what the effective overlapping is not there and hence p pi p pi bond does not form okay now the second type of bond we have here which is p pi d pi p pi d pi right now since carbon does not have d orbital since carbon does not have d orbital in its valence shell its valence shell it does not form p pi d pi bond it does not form p pi d pi bond but other elements of group 14 has tendency has tendency to form p pi d pi bond right so on the basis of this only we have examples and I think I have done this example and this kind of bond p pi d pi bond is very silicon has very strong tendency to form this kind of bond like on the basis of this only if I write down this example si h3 whole thrice n and ch3 whole thrice n which one is more basic here which one is more basic into these two which one is more basic ch3 whole thrice n yeah you see what kind of base is this this is louis base right electron pair donor what happens here you see this has lone pair and this also has lone pair but since here we have silicon which has vacant d orbital the silicon has vacant d orbital so this lone pair is donated to this vacant d orbital of silicon to form p pi d pi back bonding okay and hence this lone pair is not available here and hence it is not a base weaker base yeah but here since carbon does not have d orbital no d orbital so this lone pair is available here so it can donate to the other molecule this behaves as a louis base understood yes understood this is important example okay must remember this okay next write down reactivity towards oxygen reactivity towards oxygen write down the elements of group 14 the elements of group 14 when heated with oxygen the elements of group 14 when heated with oxygen forms an oxide of forms an oxide of mo2 type mo2 type this is as you can see it is dioxide and this is monoxide one note you write down here all these small small notes points are important write down si o exist only at high temperature at high temperature where it is where it is reduced sorry where it is exist at high temperature just a second where it is formed by the reduction of si o2 dioxide with si silicon itself so the reaction will write down si o2 plus si gives you two si only at high temperature reactivity towards water reactivity towards water write down carbon silicon and germanium carbon silicon and germanium do not react with water do not react with water okay no issue carbon silicon and germanium do not react with water however on red heating red heating means what strong heating also you can assume at high temperature however on red heating these elements except lead important this one these elements except lead decomposes a steam except lead decomposes a steam you see carbon solid form plus h2o plus h2o on red heat gives co plus h2o gas si solid react with 2 h2o on red heat it gives si o2 plus h2 sn solid plus h2o gives sn o2 plus h2 gas but no do you write down lead is not attacked by is not attacked by pure air free water pure air free water except at boiling point except at boiling point except at boiling point next line it is it is easily corroded by water it is easily corroded water containing dissolved air containing dissolved air forming lead hydroxide forming lead hydroxide lead hydroxide which is soluble in water which is soluble in water this property you have to memorize which is soluble in water this reaction you write down 2 pb plus 2 h2o o2 gives pb OH whole twice soluble in water this one this last one point to write down the solvent action of water solvent action of water is known as is known as plumboso valency b o s o plumboso valency nothing we have to understand here the point here it is what that lead is generally not attacked by pure air free water except at the boiling point what happens if you have air dissolved in water right and that air contains oxygen so this oxygen is coming from air if water contains air in it right and when it reacts with lead it forms pb OH whole twice which is a water soluble right this is it we have so the point is all these elements reacts with water but lead generally does not react with water right it it reacts with water but that water should be pure and air free right if it is not air free then it forms pb OH whole twice which is again water soluble now we see some general characteristics of compounds okay we'll see the compounds of this group and its characteristics the first one you write down hydrides hydrides write down these elements forms covalent hydride covalent hydrides like we have for carbon also those will discuss this in the last okay let me finish this first the hydrides of carbons are what alkene alkene alkynes correct you already know this hydrides of carbons are alkene alkene alkynes aromatic hydrocarbons and all write down few points into this write down germanium hydrides are straight chain compounds straight chain compounds write on the hydrides of tin the hydrides of tin we call it as stanon hydrides of tin sta double n a n e stanon for germanium we call it as germanium hydrides or you also call it as germans both are same thing this stanon you write down these are less stable and strong reducing agent next write down this is done next write down acidic character of oxides oxides we have already discussed that it forms two types of hydride one is mono and other one is dia mo2 type okay write down as we do as we go down the generally we discuss about dioxides which is generally more stable state write down for dioxides as we go down the group for dioxides as we go down the group the acidic character decreases acidic character decreases and basic nature increases right down the group acidic character decreases and basic character increases so if i write down co2 si o2 sn o2 and pb o2 so down the group acidity decreases and basicity increases can you tell me the reason for this not stability it is acidity acidity decreases anyone can you tell me the reason yeah you can also say the accessible deorbiters to accept the pair of electrons or you can also say as we go down the group that is not true here correct see as we go down the group deorbitals are there and size also increases right so it can easily accommodate the pair of electrons and that's why the acidity basicity increases acidity decreases next you write down halides halides you write down write down all elements of this group yeah stability of plus 4 will decrease down the group write down all halides of sorry all elements of this group forms tetrahelides forms tetrahelides mx4 type tetrahelides of mx4 type okay write down write down among simple tetrahelides among simple tetrahelides the tetrafluorides fluorides fluorine geo has amphotonic character it is not completely acidic or completely base among simple halides tetrahelides the tetrafluorides of carbon silicon and germanium the tetrafluorides of carbon silicon and germanium are gases exist in gaseous form however this snf4 and pbf4 is are actually solids why because these are halides are covalent in nature and because of its covalent nature it is a volatile gas not important only the state sometimes asks gases are solid these two halides are have any character this is also you remember any character tetrafluoromethane cf4 will discuss few points just few facts we should know first of all since it is tetrahelides all atoms are sp3 hybridized for halides carbons are sp3 hybridized okay cf4 write down it is carbon tetrafluoride write down it is exceptionally unreactive gas and highly stable cf4 write down it is exceptionally unreactive gas and highly stable right the preparation method of cf4 is what when this co2 carbon dioxide is allowed to react with sulfur tetrafluoride it gives cf4 and so2 displacement kind of reaction it is this is the laboratory method of preparation laboratory now the industrial method is what we use chlorofluoromethane right which is you know cf2 diphenol diphenol when this is allowed to react with fluorine itself it forms cf4 and chlorine evolve now why we are discussing this here because this is actually a monomer cf4 right it is dimer if you see cf4 the dimer of cf4 is okay just a second it is not it is dimer just a second just a second see we get cf4 carbon tetrafluoride but there are also possibility of getting of ended up getting hexafluoromethane into this which is nothing but c2f6 or we can also get tetrafluoromethane which is c2f4 hexafluoromethane or tetrafluoromethane now this c2o4 which is tetrafluoromethane when it is polymerizes to c2f4n this we call it as poly tetrafluoromethylene okay this is what poly tetrafluoromethylene PTFE poly tetrafluoromethylene is the polymer of tetrafluoromethane now few uses of this is important that's why I have given you this uses of this you write down poly tetrafluoromethylene poly tetrafluoromethylene uses you write down write down used as uses you write down good electrical insulator for coating non-stick pans and razor blade for coating non-stick pans and razor blade it is chemically inert in nature heavier and more dense inert in nature heavier and more dense now the last compound we'll see here write down carbonates and bicarbonates just just a second this is not required here I guess it is carbonacea this we have done not required let it be okay so the next thing we'll discuss here that like we have generally it is we have not discussed the general trends some compounds halides hydrides okay oxides the you know acidity of oxides reaction towards water all these things we have discussed inert bare effect okay now there are few compounds which is important here to understand few reactions into that that we'll discuss and then you can follow NCRT actually okay the first compound you write down that is of you know these elements are you write down heading you write down poly halogen compounds few compounds we'll discuss and the heading you write down poly halogen compounds the first compound in this write down dichloromethane dichloromethane which we also call it as methylene chloride methylene chloride what is the chemical formula for this can you tell me methylene chloride what is the chemical formula CH2Cl2 correct dry chloromethane okay you see it is prepared by direct chlorination of methane and we have done this in organic Cl2 H nu right and then with Cl2 H nu we'll get CH2 Cl2 CH2 Cl2 the another method of preparation is what when chloroform write down we can also prepare it by the reaction of chloroform with metal and acid reduction of chloroform chloroform with metal and acid which is nothing but ZN plus HCl metal and acid we use what is the formula of chloroform do you know the formula of chloroform what is the formula chloroform is CHCl3 okay CHCl3 so when you do this reaction CHCl3 reduction ZN and HCl so it forms CH2Cl2 plus HCl this is the two preparation method of dichloromethane we have which is not that much important what is the use of this it is used as a solvent inert solvent we have already seen this okay inert solvent it is we can also use this as paint remover paint remover metal cleaning metal cleaning and finishing solvent finishing solvent manufacturing drug there also we can use this as a solvent manufacturing drug this is actually harmful for human also right because it harms the central nervous system right few things i'll just tell you just listen to me on exposure of CH2 Cl2 in air it leads to slightly impaired hearing and vision okay so that's a no harmful effect we have on human because of this you can have nausea dizziness numbness numbness in the fingers actually right direct contact with the skin it causes burning sensation and mild redness of the skin will be there if a direct contact with eye it will burn your cornea okay so it is very harmful actually right so we always use this whenever use this in laboratory we take a lot of you know measures it can possible see it depends like the exposure to what extent you are in you know influence of these things if it is little bit you will have slightly you know burning sensation and all but if it can burn right and if you have exposed to it to a very large extent then it may knock people out it's not a big deal right depends on what extent or what amount it is there depends on that okay so these are the few you know uses and and what we say the harmful effects we have which is actually you know using school exam botism right on uses and harmful effects or like that okay how it is harmful to human this kind of questions for one or two months usually they ask that's why i've given you this in jay they don't ask all this question okay so the next compound you write down is trichloromethane trichloromethane trichloromethane is chcl3 which is chloroform right now it is used in the manufacturing of it is used in the manufacturing of freon refrigerant what is the refrigerant it is used in the manufacturing of freon refrigerant freon refrigerant which was like it has f22 and the molecular formula is c2f2 cl4 this is also the same thing it caused dizziness headache right if you have exposure to this to a large extent it may cause damage to liver right kidneys it is also widely used in anesthetic like an anesthesia for an anesthetic purpose we use this as an anesthesia because of its toxic in nature it is toxic in nature right but since it is toxic so nowadays we don't use this as an anesthetic it is again how do we manufacture this it is again manufactured by the chlorination of methane right so write down the single one line here it is manufactured by the chlorination of ethane chlorination of ethane when it reacts with oxygen in presence of air in presence of light when it reacts with oxygen in presence of light it forms phosphine gas for seen gas for example you see chcl3 when it reacts with o2 in presence of light it forms phosphine which is cocl2 plus hcl this is phosphine g e n e one more point to write down when phosphine reacts with ethanol when phosphine reacts with ethanol it converts into diethylcarbonate it converts into diethylcarbonate which is harmless so phosphine is this two c2h5 OH HCl and HCl goes out so two moles of HCl goes out C double bond O and this will join okay you see this H and this CL goes out so it is joined with C2H5O C double bond O O C2H5 plus two moles of HCl we get here so this phosphine gas it is actually toxic in nature so when it reacts with ethanol it forms harmless diethyl ketone this is again one reaction we have write down it can also be prepared by hydrolysis of chloral hydrolysis of hydrolysis of chloral by COH whole twice it can also be prepared by the hydrolysis of chloral by COH whole twice so you see what is chloral here suppose we have ethanol CS3CHO when it reacts with CL2 in presence of COH whole twice chlorination then it forms CL3CCHO plus three moles of HCl so all these chlorine atom knocks out these hydrogen atom here and forms HCl just a second okay I'll tell you what is the use for phosphine right this we call it as chloral right now when this chloral is allowed to react with COH whole twice which is nothing but this like this if I write down plus we have CL3CCHO and we are taking two moles of this here so CL3CCHO two molecules we have here right so the product we get here is two molecules of CHCl3 plus HCOO whole twice CA so here what happens this H combines with this CCL3 and knocks out as CHCl3 this is how we prepare chloroform right now like you said what is the use of phosphine okay phosphine actually used to prepare this COH whole twice with removal of CL2 you see here CAO CL2 I'll write down this reaction which is probably this this is phosphine and when it is react with water and is put into water it forms slag lime which is CAOH whole twice and chlorine evolves here chlorine gas right which we further use here chlorine gas we further use here with ethanol for the preparation of chloroform further if you react this with water you'll get phosphine again few points write down here like it is few points write down quickly it is a sweet smelling colorless liquid it is a sweet smelling colorless liquid which is immiscible with water and miscible with organic solvent immiscible in water and miscible in organic solvent next line it is slowly oxidized by it is slowly oxidized by air it is slowly oxidized by air in presence of in presence of light in presence of light to a poisonous gas in braggartite right on phosphine to a poisonous gas in braggartite right on phosphine hence it is stored in colored bottles hence it is stored in colored bottles which is completely filled which is completely filled so that air is kept out the bottle must be completely filled so that air is kept out one important reaction of this i'll give you one already we have done that is idoform reduced with silver it gives you acetylene two moles of idoform is used see phosphine is a you know toxic gas okay so like you know the chemical warfare if you see you must have heard that in you know somewhere in iraq or syria russia has used some chemical weapon you must have heard that in the news yes this all these things that i have given you now it is for chloroform c h cl 3 not for fasting have you heard this that russia has used some chemical weapons against syria right which was not actually right it was just you know just as an allegation on russia that that he has used it is not we are not very sure that he has used it or not actually okay but the point is what is that chemical weapons chemical weapons are you know are those kind of weapons that we have which when you explode it some chemical reaction takes place and it releases a very toxic gas which actually gives you know some skin sensation some burning and some you know business or or you know some kind of nausea you'll get okay or even if it is more toxic and if someone in health it will die also so that since fasting is also a toxic gas so we can use this into the chemical weapons that's that's that's the thing it's right chemical warfare we use it okay chloroform also we use but it depends again right you know when the reaction takes place so these kind of toxic gases we can always use in chemical warfare for you know chemical weapons that's true right basically all those gases which are you know harmful for human okay those gases we can use and there are possibilities that with few reactions this can give even more toxic gases so those kind of reaction we use to you know we make them happen in chemical weapons so this is a thing right so so one reaction that you have already seen when iidoform reacts with silver it gives you acetylene right in preparation of alkyne we have done that another reaction you see here so in case of like for instead of iidoform we can also use chloroform over there you'll get agCl another reaction you see here if this chloroform CSCl3 is allowed to react with HNO nitrous acid it gives you Cl3NO2 plus H2O right this we call it as chloropikrin PIC RIN chloropikrin which is used as tear gas which is used as tear gas so this is a few compounds also we have discussed i like you must go through with NCRT first of all all the things you have studied from NCRT and like i haven't discussed about glass okay different types of glasses that you must go through with NCRT only composition things you have to memorize about glass you must study okay and some behavior anomalous behavior of carbon behavior of carbon basically NCRT you have to go through from beginning to end okay and few more compounds are given in NCRT which you can go through so that that may help you in the exam okay the board exam that you have but this is a glass thing i have seen few questions on to this they ask some parax glass and all some companies types of glasses okay you just can go through and there are probably few structures of the compounds of silicon also it is given if it is not you let it be but you just go through with that okay so this is it we are done with this one more thing i forgot to tell you you have to go through with allotrops of carbon also diamond graphite no buckyballs phylidines all those c60 it is given in NCRT okay so that much is enough like if i if i give you now i'll just dictate your theory so i am not giving you that because it is given in NCRT you can go through with that okay so allotrops of carbon is also important understood we'll take a break now okay i'm tired of contain Islam is speaking in right so i'll take a break now 10 minutes break we'll take so it's already 6 10 we'll start at 6 20 or 6 12 something like that 6 22 yes we'll take a break and then we'll start okay then we'll discuss geolites also okay we'll take a break now we'll start in 10 12 minutes