 So here we are going to discuss the questions of J e-mail 2019. This question was asked in the first shift of 9 January. So we are going to, in this session, we are going to discuss five questions from question number 21 to 25. So this is again a memory based question we have. So the final or the actual questions which is asked in J e-mails, which may or may not be a bit different from this. This is data-wise enough. So that's what you have to keep in mind. It is all the memory-based question. So you see question number 21, reversible isothermal expansion of gas for two temperature T1 and T2 graphs is given. We have to find out the graph, like the four graphs are given here. So we have to find out which one is true. Right? So first of all, the process is reversible isothermal expansion. And in reversible isothermal expansion, the work done can be given as minus nRT ln Vi or V1 by V2, Vi by Vn. This is initial and this is final. Or we can also write it as work done, W is equals to nRT log or ln V2 by V1, V final minus V initial. So you see this work done, W is equals to, we can write nR ln V2 minus nRT ln V1. So this is the work done at a given temperature T. Right? You see this is, if you see the equation here, it is Y is equals to m, X and C. Right? So first of all, the intercept here, it is negative. Right? Negative intercept. Second one, the slope m depends upon, depends on temperature. So obviously in the second case, because T2 is greater than T1 we have here, the slope will be more than the first case. And negative intercept means what? It will cut the Y axis below the origin. Right? So if you see, this graph is, here it is going above the axis. This one is fine. This one is fine. But this one is going above the origin. So hence, first option is not true. Second is also not true, passing through origin. Right? Fourth one and third one is also not true with the same logic. Only fourth option we have, where the intercept is negative, slope also you see. In the second case, it is more than the first case. Right? That's why for this question, option four is correct. Next question. Consider following compound A, yellow, B, wallet. This is the following is incorrect. Okay? The splitting in A is less than to that of B. Incorrect. We have to find out. Correct? So B, you see we have NS3 comparatively stronger ligand than H2O. So obviously the splitting in B is more than to that of A. So first option is correct. Okay? Second option you see the crystal filled splitting parameter can be measured by the wavelength of complementary color for A and B. Right? So that we observe is nothing but the complementary color. Right? So with the wavelength of that color, we can find out the energy because we have this relation E is equals to Hc by lambda. Hc by lambda. Right? So crystal filled splitting parameter we can easily find out because we know the complementary color. We have lambda for that and then we can find out the energy. Right? Which is the crystal filled parameter. You see the first compound chromium is in plus three oxidation state. Okay? Because H2O, this is minus three, so this is plus three. The, you know, electronic configuration of chromium is argon 4s13d5. So when you write down the electronic configuration of plus three, one electron will come out from this 4s and two comes out from 3d. So its electronic configuration will be 4s03d3. So this is, this has three unpaired electron because again, the pairing does not take place because the ligand is V. Similarly, you can find it out for chromium also. It is fine. Right? So plus three is what we have. So it is, you know, again, three unpaired electron will get into this also. Third option is also correct. Okay? So fourth will be the answer. Now you see the fourth option, the crystal filled sprinting parameter can be measured by the wavelength of yellow and violet colors of A and V, which is not true. Right? This option is not true. Hence the answer will be option fourth. Right? We cannot find out the parameter from this yellow and violet color over here. Right? Hence option fourth is not correct. Hence it is the answer. But 22 answer is option fourth. Which of the following properties are true for silicon polymer? Okay? This is actually, you know, a factual question you have to memorize this. Hydro, hydrophobic in nature it is fine. Okay? It is water repellent actually. That's why it is hydrophobic in nature. And silicon also you can easily understand why it is hydrophobic. Resistance towards oxidation and used in Greece. That is also true. This option is also true. So B and D are true easily. So we have B and D in third and fourth option. Right? First of all, thermally resistant and have low dielectric also. That is also true. The silicon polymers, thermally it has, you know, heat resistant it is and it's dielectric constant is low. Right? Whenever it is any molecule, it is heat resistant or thermal resistant. It must have low dielectric constant. Okay? And this polymer is also biocompatible. Okay? So this is, that's why it is very useful for any purpose. So for this question, I think all the four options are true. So we can easily write down the answer as fourth option. Correct? This is actually, you know, you have to memorize the property. Memorize the properties of silicon polymer. This is actually the direct properties we have. 0.05 Faraday charge is passed through a latest storage battery. Anodic reaction, what is the amount of PPSO4 precipitated? Okay? So you see the reaction here it is the solid lead which is PBS solid plus SO4 2 minus gives PBSO4 plus 2 electron. So 2 Faraday of charge we are using here because 2 electrons means 2 Faraday of charge. Right? So when 2 Faraday of charge passes through charge amount of PBSO4 deposit is equals to its molecular weight. This is the direct, you know, the concept of this we have. Number of electron release that much Faraday when it is passes through then the molecular weight of the substance will get deposited. 303 gram will get deposited. But this is for 2 Faraday but we are not using 2 Faraday here but we are using 0.05. Okay? So for 0.05 the mass that deposited here is 303 by 2 into 0.05. Right? And when you solve this you'll get 7.6 gram. So answer will be option 3. Right? It's that easy question. Question number 25th. This is the following piezoelectric material. Okay? The answer for this will be quartz. Quartz is a piezoelectric material. What is piezoelectric material? These are the material which produce electrical current under the influence of any mechanical stress. Okay? So piezoelectric material are those material which produces electric current, electric current when they are placed under mechanical stress. Right? So again you have to memorize this. Quartz is a piezoelectric material which is very common actually. You must have studied this in 9th or 10th grade also. Right? So these are the five questions we have discussed. Okay? Is this an endearment exam? Okay. Thank you.