 to write down oxides, all elements of group 14 mainly forms two types of oxides that is mono oxide and dioxide, C2 and COD, mainly two types of oxides mono oxides and dioxide. Write down lead also forms an oxides of an oxide of Pb3O4 type, this kind of oxides lead forms actually considered to be the mixture of PbO and PbO2. PbO2 and PbO2 and PbO2, PbO2 and PbO2. You see FE341, I think we have discussed already. Can you tell me the amounts of EVO and EVO? Wait a minute. Can you tell me the oxidation state of iron here of each iron atom? One is plus two, the other one is plus three. Plus two is plus three. Right. Why is this so? Because this exists in the form of FE4 and then FE2O3. Right. So it is actually the addition compound. FE0.FE2O3 is nothing but FE3O3. So is it the opposite? This one. Yeah. It is not a solid. It is oxide. So this will be, I think it is 2PVO and PVOO2 because only mono and dioxide it forms. Right. So MO and MO2 type. So it is 2PVO and PBO2 type. So if I ask you what is the oxidation state of each lead atom in this oxide? P with PVO4. I haven't asked this side of this question but this one they have asked many times. But it is similar. Right. So if I calculate oxidation state here it is minus two. So here it comes eight by three which is the average value. Right. But oxidation state of each lead atom is plus two here and here it is plus two and plus four. So total is what? Two into two plus four plus four eight divided by three. Eight by three is the average. Okay. So in PB3O4 the oxidation state is plus two and plus four. You must remember. Okay. Now you should write down. Write down. As we go down the group next slide in this. As we go down the group the acidic behavior of dioxides acidic behavior of dioxide decreases. Basic behavior increases. The CO2, CO2 is most acidic and the last one is what? O2 is basic in nature. It is the same. If you dissolve this in water it can release S plus. Okay. That's why it behaves in acid. Okay. The charge density is higher. It cannot lose H plus in aqua solution. Okay. That's why there are basic differences. Write down. Next slide again. Due to inert pair effect. The plus two oxidation state of lead is more stable than plus four. More stable than plus four. Just lead. Just lead. Not the other one. See it's relative. It is very strong in the last compound. Last element. That's why I'm talking about lead. But in that other one also you can say. Plus two is more stable than plus four. And hence with plus four oxidation state. Let me just write down. Pb four. Lead with plus four oxidation state behaves as a strong oxidizing agent. Pb O2 plus H2O4. Or it forms. Pb S O4 plus H2O plus O2. Pb S O4 plus H2O plus O2. H2O plus O2. You see the oxidation is said here it is plus four. And here it is plus two. Next write down halides. Write down. These elements combines with halogen. All these elements combines with halogen. And forms halides of Mx4 type. Combines with halogen. And forms halides of Mx4 type. See few reactions we have done. Carbon like there are many compounds derivative of alkene. We have CH2, CH2, di-chloromethane. We have C-H-Cl3, tri-chloromethane which we also call as chloroform. C-H-I3 is derived iodomethane that is iodomethane. C-Cl4 is tetra-chloromethane. So the most important compound in this we have. C-H-Cl3, organic chemistry also we see. Idoform test, chloroform test. C-H-Cl3, C-H-I3 is also important. Okay, so we will discuss these two compounds first. Write down first C-H-I3 tri-hydomethane. C-H-I3 tri-hydomethane. It is prepared by, it is prepared by Idoform reaction. Idoform reaction. Mechanism we will not discuss here. We will discuss that in organic chemistry. Idoform reactions are those reactions. In this the reagent we use is NaOH, sodium hydroxide with I2. This is the reagent for Idoform reaction. Okay, and all those molecules which contains C double bond O, methyl ketogrode. C double bond O CS3. This group if it is present then it can show positive Idoform test. Positive Idoform test means what? This on reaction with NaOH-I2 suppose we have CS3 here. It converts into C-H-I3. Idoform forms in this reaction. And hence it gives positive Idoform test. Okay, so what you have to memorize? The molecule which has methyl ketogrode present. Even alcohol which on oxidation gives methyl ketogrode. Like for example, we know 2 degree alcohol on oxidation gives ketone. Suppose we have this reaction. This can also shows Idoform test. Because this part if it goes under oxidation it forms CS3 C double bond O CS3 which converts into methyl ketogrode. And hence it shows Idoform test. Example this question they ask many times. They will give you 8 to 10 molecules in integer time. And they will ask you how many these molecules shows positive Idoform test. Okay, so condition is what? Methyl ketogrode. If you have 2 degree alcohol that will also get oxidized into this. Hence this also shows some test. So reaction it Idoform CS3 CO CS3 with NaOH-I2 gives CS3 I3 plus CS3 CO Na NaI and then water. We will discuss in organic chemistry. 4 moles of NaOH we use and 3 moles of I2 we use for this purpose. 4 moles of NaOH and 3 moles of I2. So this is the preparation method of Idoform. Idoform reaction. Okay, next write down chloroform. It is obtained by chlorination of methyl. What is the reaction? Chlorination of methyl? No, the mechanism is free radical. Write down chlorination of methyl. This reaction we have already discussed. CH4 plus Cl2 gives CHCl3 plus HCl. Okay, one is chlorination of methyl. Second one plus HCl. Second method of preparation. It is obtained from the hydrolysis. Hydrolysis, sorry, the reaction of clodal with clodal. C-H-L-O-R-A-L. Clodal with CaOH whole twice, calcium hydroxide. Clodal is this molecule. C-H-O-Cl3, this is clodal. Okay, this is clodal. We will take two molecule of this. C-H-O-Cl3 and this is hydrolyzed with CaOH whole twice. Okay, the product here we get is, see this H and this C-Cl3 combines. We will get two molecules of C-H-Cl3. And we will get a source of this. C-A-O-C double bond O-N. Next slide down. Phenomenon by which? Phenomenon by which? By which? An element exists in. Exists in two or more. Two or more. Different crystalline or amorphous form. Two or more. Different crystalline or amorphous form. Are called allotropic forms or allotropes. Sorry, what is the first line? Phenomenon by which? Phenomenon by which? Okay. Allotropy are called allotropy. And these different forms are allotropes or allotropic forms. And these different forms are called allotropy. And these different forms are allotropes or allotropic forms. Okay. Carbun, how many different allotropes here for Carbun? Three. Three crystals. Diamond, graphite. Diamond, graphite. This two, this two, you know, what is the, like two, three points you shouldn't go into this one. What is the hybridization of Carbun and Diamond? Graphite. Arrangement. Here we have tetrahedral and here we have layer destruction, right? Layer destruction. Each Carbun atom has speed to hybridize. Okay. Which one is conduct, like beers as a conductor? Graphite. Okay. This property is new. You should know the properties of this because sometimes in the exam they ask this question also. Like properties, three, four options they'll write down. You have to choose the right one or wrong one. Okay. You should know the properties. Next one you write down. Write down the chemical properties of this thing, Carbun. Chemical properties. First point you write down. Combustion. It shows combustion reaction, allotropic form. Right. Energy releases. Exothermic, always exothermic energy releases. Limited supply of air, what it forms? Monoxide. In excess of air it forms dioxins. Okay. Next one. Carbun behaves as a reducing agent. Behaves as a reducing agent. Behaves as a reducing agent. It reduces many metallic oxides. Reduces many metallic oxides into corresponding metals. One reaction you write down. PbO plus Carbun C is Pb plus C is Carbun monoxide. H2O plus Carbun. Red heat. What it forms? H2O plus C. CO plus H2O. CO plus H2O. CO plus H2O. What we call it as? Water gas. Water gas, sin gas, synthesis gas, all the same. Right. This reaction is H2O plus Carbun. What is producer gas? CO plus H2O. CO plus H2O. Okay. CO plus H2O.