 Okay, we have is which of the following is piezoelectric material. Okay. So first of all, this is a fact based question. Okay, you cannot put any logic into it. So the answer of this question is quarts. Okay, quarts is a piezoelectric material. This is a memory based question. Piezoelectric material are those material which can produce current definition you may keep in mind produce current when put under when put under mechanical stress mechanical stress. Okay, piezoelectric material are those materials which can produce current when it is under mechanical stress. There will be quarts this you have to memorize. Okay, there is no, you know, back here. There's no logic here. Sorry. Next question number 26 is a following isotope of hydrogen. Very simple question. The answer will be option third. I don't think we even need to discuss this one also. DGDM, DGDM and proteam. Okay, very simple and straightforward question. Question number 27. In hydrogen emission spectra, the electron transition takes place from n is equals to 8 to n is equals to f. If you plot the graph, okay, so we have to find out the slope thing intersecting slope. Okay, so what is the, you know, relation we have here wave number, that is new bar, which is equals to one by lambda, which is equals to R h z square bracket open one by one by NF square minus one by ni square. Okay, R z you let it be as it is R h z is for hydrogen it is saying hydrogen emission z value is one NF we do not know so one by NF square minus one by eight square is 64. That will be is equals to R h by NF square minus R h by 64. Another graph here it is what graph of this and one by NF square. Okay, we have new bar this and this. So slope of this will be what slope is nothing but R h and intercept will be minus R h by 64. Right, so we have R h positive slope. So option two is correct here. Okay, next question number 28. Aluminium exist in plus three oxidation state where thallium exist in both plus one and plus three oxidation is still the reason for this. Okay, so you see as we go down the group, down the group, the electron starts filling the electron, it starts filling into after this F orbital. Right, this DNF orbital shows weak screening effect. Weak screening because of this also the size decreases and that contraction in size we call as a lanthanide contraction. Okay, size decreases we call as a lanthanide contraction. But here we are talking about the stability of oxidation state. So thallium actually thallium exist in plus one and plus three oxidation state. Right, but in this one, the plus three oxidation state is is more stable, is more stable, because two electrons which is there in the another orbital, that becomes inert, inert towards any reaction, any reaction. Actually, the if you write down the electronic configuration of this inertial orbital will have two electron and after this will have one electron and here we have D or F orbital present. Okay, so what happens because of this weak screening effect of DNF orbital, these two electron is strongly attracted towards the nucleus. Okay, and this has very less tendency to take part in any reaction. Right, that's why thallium has very less tendency to form plus three oxidation state which is only possible when this two and one one three electron will take part into the reaction or it will you know eliminate it will release these three electrons. Then only plus three oxidation state is possible. Since this two electron is strongly attracted towards the nucleus, hence the plus three oxidation state of thallium is very difficult to form and thallium generally exist in plus one oxidation state. So it is more stable in plus one oxidation state. Since the pair of electron becomes inert because of the weak screening effect of DNF orbital, that's why this effect we call it as inert pair effect. The answer for this question will be inert pair effect. 28 question number option number one is right. Next question. Maximum spin only magnetic moment for transition metal complex maybe. Right, so what is the formula of spin only magnetic moment? The formula is this root under N into N plus two DM. This is the formula of spin only magnetic moment for maximum spin only magnetic moment and is the number of unpaired electrons so N value will be five N can have maximum value as five five unpaired electron can be maximum possible for any transition metal. Right, so what N value is five so we can calculate this directly five plus two seven seven two five is 35 so root over of 35 so it is slightly less than six. Okay, so only one option is there which is really less than six five point nine two BM option one is correct. Just a second. Hello. Thank you. Okay, so question number 29 option one is correct. Next question 30 for a given mixture of point four moles of gas a and x moles of be okay so we have a mixture of a and b a and b number of moles of a is point five. Number of moles of B is x temperature is also given that is 200 Pascal sorry pressure is given. 200 Pascal temperature is 1000 Kelvin 1000 Kelvin we have to find out the X okay so number of moles of this so volume is also given 10 meter cube 10 meter cube. So we can simply apply PV is equals to an RT because it is a gaseous mixture both are gas correct so pressure is 200 volume is 10 number of moles is. 0.5 for a and x for be are you let it be are because there is option in terms of our only temperature is 1000 this 1000 this zero will get cancelled. So point five plus X is equals to be two by R X is equals to two by R minus one by two that is equals to four minus one by four minus R by four minus R by two are option first is correct. So there is a last five question that we have discussed thank you.