PHYSICAL CHEM TEST-17 VIDEO SOLUTION FOR RE NEET-2026

[00:00:00]Goal Nations [Music] Leading Institute Hello Students, I am Deepak Deep going to discuss Physical Chemistry part of test number 17 of test series for REET 2026.

[00:00:20]It was held on 12th June 2026. Let's start with the first question of Physical Chemistry and it is question number 143 on the board. A Let's focus on question number 143. Question No. 143 is After removal of hard cells from two eggs, in fact one of them is placed in pure water and the other is placed in saturated solution of sodium chloride.

[00:00:43]The correct observation brother, if we remove the hard shell on top, that is, remove the calcium carbonate, only plasma will remain. And now if you put that in the animal bladder, the animal membrane, it will allow you to have inflow and outflow of solvent. Will behave like SPM. So when you put it in a fresh water solution, it will swell because endosmosis will occur. The solvent will slowly move in it and if you put it in a concentrated NaCl solution, because the concentration is higher outside, then it will move the water out of the cell, out of the egg, and then exosmosis will occur. So let's check the answer. Eggs placed in pure water will swell. correct. So far it seems right. This will be swell brother.

[00:01:32]Why will it swell? Because the concentration of protein is low inside the egg as compared to water. This is messed up. The concentration of protein is higher inside the egg. That's why the water is moving inside. To bring the concentration to equilibrium. So till here it was fine. But the explanation given is wrong. So first is incorrect. Egg placed in sodium chloride solution will solidify due to osmosis.

[00:01:57]This looks right. Osmosis will be whatever and osmosis of osmosis. A general thing is written. So it will shrink and its size will become smaller in NaCl concentrated solution. So this is correct. Egg placed in sodium chloride solution will swell due to movement of water out. Brother, if the water comes out then there will be no swelling. That will shrink. The wrong statement is the third one. An egg placed in pure water will shrink because the concentration of protein is high inside the egg as compared to. Why would it shrink now? When the protein is high inside then it will swell.

[00:02:28]So this is also wrong. The answer is the second one. Second answer of 143.

[00:02:35]After question number 143, see question number 144.

[00:02:41]The radii of this stationary state of h atom r is expressed as brother, the expression of radii is a not * by n² and in fact by z. Now that h atom has been said, z has been defined as one, even then it should be a not * n². He has said n, child, so the first statement is wrong as n increases, the value of r increases. Yes, if n increases, then this overall value will increase. This is a correct statement. The orbit number will increase.

[00:03:16]As you move into higher orbits, the radius of that orbit will increase.

[00:03:22]So, the first statement is wrong and the second is true. So, the answer is statement two is true and statement one is false. Children answer fourth. Forth of 144.

[00:03:40]See question number 145 on the board. The weight of a molecule of the compound C6H12O6. I need the weight of a molecule. You know the molecular mass of C6H12O6 is 6 * 12 + 12 * by 1 + 6 * 16, if we add this then the mole comes to 180 grams.

[00:04:06]Meaning, for one mole of glucose, what is the molecular mass of one mole of glucose, children? 180 grams. Meaning 6.022 * 10 to the power 23 molecules correspond to 1 mole and what is its mass kids?

[00:04:26]180 grams. So brother, what will be the mass of one molecule? For one molecule it is 180 and if we approximate it then 6 * 10 to the power 23 so six times this is 30 times 30 * 10 to the power -23 now there is nothing like 30 so if we bring it to one digit in decimal then 3 * 10 to the power -2 grams will be the answer so the answer is 3 * 10 to the power -2 grams second answer 145 see question number 148. In the plot of molar conductivity versus square root of concentration, following curves are observed for two electrolytes. Brother, you know that strong electrolyte decreases regularly and weak electrolyte decreases rapidly at lower concentration due to more ionization and at higher concentration it starts decreasing less. So this line A is for strong electrolyte and line B is for weak electrolyte. So you have to find out respectively A and B so for strong and weak answer is second one. It is a very well known curve. You know that when you talked about conduction, lambda mλe, you said that there will be regular decreases in strong electrolyte and this regular decrease will not happen in weak electrolyte.

[00:05:53]More decreases and increases at lower concentration only due to more degree of anion. In that, alpha is inversely proportional to the square root of C.

[00:06:01]You have read this. Ost dilution law works.

[00:06:08]Question number is 149. Next the reaction order from the following rate constant. Brother, the value of the constant is not important. This unit is important.

[00:06:19]You know that the unit of K, baby, is mole per liter to the power 1 - n per second. So if you look at that, one means this mole will be to the power 1 - n.

[00:06:36]liters to the power n - 1 and per second. If there I see power-1 of mol.

[00:06:42]This means the value of 1 - n is -1. So what value of n should come out, child?

[00:06:48]Two. So we can see this second order kinetics by comparing the power of one of them.

[00:06:53]Accept it for a second because it is permanent. Either you can look at the moles or look at the litres. You will understand from this.

[00:07:03]After question number 149, please see 158. The Oxidation State of Chlorine in Calcium Oxychloride. Well, CaOCl2 you know, is bleaching powder and it is made up of one calcium ion, one chloride ion and one oxy chloride ion. Brother, here chlorine is at -1, it is clearly visible.

[00:07:26]And the chlorine here, because the oxygen is at -2, is at +1. This means that there are two states of chlorine in bleaching powder. One +1 and the other what kids? -1. So let's give the third answer as 158.

[00:07:43]See question number 159. 1 litre of water contains 20 mg calcium 12 mg magnesium ions What is the volume of two normal sodium carbonates required to soften 5000 litres of water? Brother, the hardness has to be removed. So you know that this is less a question of hardness and more a question of titration.

[00:08:06]Whose equivalents will be spent as much as the total of milli-equivalents of calcium and magnesium?

[00:08:09]of Na2CO3. So the equivalents are equated.

[00:08:11]We're going to tell kids [sound of clearing throat] that the number of equivalents of calcium plus the number of equivalents of magnesium is going to equal the equivalents of Na2CO3.

[00:08:31]Just do the equation. Calcium 20 mg 20 * 10 power -3 / 20 20 is the equivalent mass of calcium. The atomic mass of calcium is 40.

[00:08:43]Valency is two. Plus magnesium 12 mg 12 * 10 power -3/12 12 is again its equivalent mass. And this thing that has come to us, children, is equivalents in 1 litre.

[00:08:57]And how many liters do you need to do it? 5000 K. So this whole value is multiplied by 5000. There will be this many equivalents in total 5000.

[00:09:07]And this will be equal to two normal * volume. The volume that comes will be in liters. So to simplify, 20 plus 20 cancels out 12 plus 12, which is 10 power -3, 10 power -3, meaning 2 * 10 power -3 * 5000. And if we divide this by two, it will be v. So, two plus two cancels out, so v comes out to be 5 liters.

[00:09:31]Children answer third. You look carefully. What did we do?

[00:09:36]Equivalent of this is equivalent of that. The same concept was applied. Whenever there is any neutralization, the number of equivalents will definitely be equal. The two things to be neutralized are calcium and magnesium and the neutralizer is Na2CO3, so the sum of both of them was made equal to the equivalents of Na2CO3. Keep in mind that the equivalent mass of calcium will be 40/2 and the equivalent mass of magnesium will be 24/2.

[00:10:05]Question No. 160 is a Matrix Matching Kids Structure of atom orbital angular momentum is under l + 1H / 2π angular momentum of electron in orbit Bohr atomic model is nh / 2π mvrnh / 2π.

[00:10:22]you have read. And the spin angular momentum of n electrons is sss + 1h/2π magnetic moment n yes here n is the number of unpaired electrons. There are two types of n in this.

[00:10:37]Because it is a standard formula. So, I have written it in matching manner as it is written.

[00:10:42]But remember, the n written in all this is the principal quantum number.

[00:10:47]He is representing Orbit.

[00:10:49]Whatever you say is the orbit number in the Bohr atomic model. But there n is the number of unpaired electrons for magnetic moment and its unit is Bohr magneton.

[00:10:57]So now you check whether your first first is four. First's four B's third B's third is still doing two matches two and three. Forest of C Forest of C. Now it has become segregated. Second option is 160. So this was a simple question. I asked using the direct formula.

[00:11:18]You must not have done any calculation immediately.

[00:11:26]Children, see question number 160 and then 162. If water vapor is assumed to be a perfect gas, the molar enthalpy change for vaporization of one mole of water at one bar and 100°C is 41 kJ per mole. Brother, Delta H is given.

[00:11:40]And delta U is the demand for one mole.

[00:11:43]Obviously, we have deltaH = deltaU + deltaNGRT and you have been given that H2O liquid goes to H2O vapor, its deltaH is given as 41 kiloJ, so okay brother, let us put our formula here, deltaH 41 = deltaU, we have to find out the value of deltaNG from one gas, zero gas means one, the value of R is 8.314, the value of T is 373.

[00:12:19]Since this value is coming in joules, so to convert it to kilojoules, we took 10 to the power of -3.

[00:12:25]So, if we multiply this by our 4, then 4 * 8 is around 3.2. So Delta U will decrease from 41 to around three, around four. So our answer will be around 3738 with positive value.

[00:12:40]So the answer is second. If you solve, Delta U will come to 37.9 kilojoules. So it was simple and not even calculative. Just had to be careful.

[00:12:53]Children always keep the unit of R in mind.

[00:12:55]You may need to convert joules to kilojoules.

[00:12:58]in joules is 8.314. Kilojoules will also have 10 to the power -3.

[00:13:04]After question number 162, please see 163.

[00:13:10]Gaseous reaction PCL3, CCL2, PCL5 shift to right direction in on increasing pressure.

[00:13:16]Brother, that is correct. By increasing the pressure the equilibrium goes in that direction only. Here the moles of gas decrease. Since the mole of product side gas is one. The reactant side is two moles.

[00:13:25]So there will be a forward shift. If we increase the pressure then the first statement is correct. When pressure increases the equilibrium shifts towards more number of moles. This is messed up.

[00:13:35]By increasing the pressure, the equilibrium shifts to the side where there are fewer moles of gas.

[00:13:39]So the answer should be given as first correct and second wrong. A is true but R is false. Answer is first. First answer of 163.

[00:13:53]After 163, you can see 165. The vapor pressure of pure liquid A is 40 mm of Hg at 310 Kelvin. The vapor pressure of this liquid solution.

[00:14:05]With liquid B is 32 mmol mole fraction of A in the solution. Brother, you know that PA A which is given is equal to P not A *. According to question P not A is given as P not A is given as 40 and PA is given as 32 this is 32 and this is 40 so 40 * ka then ka comes out to be 32 / 40 and that is 8 so let's answer first 165 first answer is a reaction is spontaneous at low temperature but non spontaneous at high temperature which one of the following is correct for the reaction brother it is happening at high temperature it is non spontaneous at low temperature means it is exothermic what is its deltaH brother negative and deltaS is also negative because deltaG is deltaH - T deltaS. In this condition it will be negative and if you keep it negative then it will become positive. So for the criterion of spontaneity, the value of deltaH should be greater than T deltaS. The value of deltaH must be larger than the mode of T deltaS.

[00:15:34]And this will happen only when there is low temperature. Meaning the spontaneity will happen at low temperature. At high temperatures the process will become non-spontaneous. So the answer is deltaH negative and deltaSH also negative. Fourth Answer: All four conditions are very important, child. This is asked again and again.

[00:15:51]If deltaH is negative and deltaH is positive. The process is always spontaneous irrespective of temperature. If deltaH is positive and deltaH is negative. The process is never spontaneous.

[00:16:04]Two conditions survived. Delta H Negative and Delta Negative Low Temperature Spontaneous. Delta H positive, Delta H positive, high temperature responded.

[00:16:13]You should definitely write this down. You can pause or slow down the video and write this down. All four are very important. It is asked repeatedly.

[00:16:26]See 170 followed by 171. The de Broglie wavelength associated with a particle of mass this much kg with the velocity of 10 metres per second. Brother, what is lambda is equal to? Simple h / mv so the value of h is 6.63 * 10 power -34 the value of mass is given baby 10 power -6 and velocity is 10 to the power of 10 will be cancelled by -5 so 6.63 * 10 power -29 and the second answer will come very simple the value has to be kept in the shape of de Broglie wavelength. If everything is given by SI then there is no problem. We put the value in SI units.

[00:17:03]Answer [nasal sound] This much meter.

[00:17:12]Children, see question number 171 and then 172. A reaction is A2B4 2AB2 at 300 Kelvin delta U & deltaS R given. The value of deltaG for the reaction is bro.

[00:17:21]Ok? First, we need to find delta H, which is equal to delta U + delta NGRT children. So Delta U is given to you 20 calories. 2 kilo calories means 2000 has been written and plus delta ng 2 - 0 is 2 the value of r to and the value of t is given as 300 so this is in calories this is also coming in calories so this will come to us 2 2 4 3 12 this 3200 calories will come to us 2000 plus 1200 now it is saying delta g tell me so delta g is equal to delta h - t delta baby delta H that you have 3200 minus the temperature that is 300 and delta S is given as a 20 so this is our 6000 and this 3200 3200 - 6000 - 2800 calories so let's answer its third yes you first get delta this is a question asked again and again in exams that delta U is given we take out delta from it and delta GG comes from delta H - t delta.

[00:18:37]So we used these two formulas.

[00:18:42]After question number 172, please see 173.

[00:18:48]The solubility of lead hydroxide in water is 6 * 10 power - 6 solubility product is bro. PBOH Whole Twice You know that PBOH Whole Twice is an AB2 type salt. Meaning when ionized, PB2 will give positive and 2OH will give negative. If the solubility is S, then this S, then that will be 2s.

[00:19:11]So KSP will be S and 2s squared that is 4s kids. So 4s we have to tell people. s is given. So ksp comes out to be 4 times the cube of 6*10 to the power of 6. So if we do this, 6 66 3 times 216 4 * 216 10 to the power of 18, so four times 216 is 864 * 10 to the power of 18, the fourth option becomes. The fourth answer of 173 will be 4s.

[00:19:48]You have read the expression of solubility equilibrium case separately for different salts. That this is also a two type salt, so we have cubed the case 4s and this will give the answer.

[00:20:01]After question number 173, see 177 which of the following molarity values ​​of ions in an equimolar solution of 5.85% weight by volume NaCl, this much percent calcium chloride 6% weight by volume and correct. Ok? The concentration of all the ions has to be found out. Let's find out the options that have been asked.

[00:20:21]Cl negative is going to come from two places, kids. Cl negative one is going to come from where is ours? from NaCl and the other one is coming from calcium chloride. One from here, two from here. Well then. Its moles will be 5.85 / 58.5 for NaCl plus the molecular mass of calcium chloride triple 1 gram is 111 grams. So this will become 5.55 /1 * 2 Why kids? Because it is going to give two chlorides and the percentage means we solve 100 below and 1000 above. So how much concentration of Cl negative will come from this? This will become one one, this will be cancelled by 100.

[00:21:09]So this forest came. Ye05 * 2 is 1 again2 * 10 Ye to molar aa to raha hai. So the first one turned out to be correct. Now let's check the calcium. The calcium concentration is just going to come from the calcium chloride. That is 5.55 / triple one moles, divided by 100 and it will become 1000. So if you look at this, this double zero double 00 cancels out and this 05 * 105 molar is coming out. So this is also correct. OH negative OH negative will come our ah from NaOH is just NaOH 6 / 40 * 10 * 1000 so this double zero double00 cancelled and four to six our 6% will go is 6 / 40 * 100 so this one and zero will be cancelled. 6/4 is 1.5 molar. So the answer is all of this fourth option. Yes, we can call such questions tough.

[00:22:22]Children can say length because all four options had to be checked. The concentration of all the ions was given.

[00:22:26]So you have every ion, all these things present in the same solution. So what will be the concentration of each of them? You must have learned it when you calculated molarity.

[00:22:35]So the answer is all of this.

[00:22:41]178 See you vapor pressure of pure benzene at a certain temperature is once non volatile non electrolyte solid is added vapor pressure becomes this what is the molar mass relative blowing of vapor pressure is a case of kids. In such a situation, to do the question, you apply Delta P / PS = WB / MB Weight of solute by molar mass of solute Weight of solvent by molar mass of solvent So we use Delta P by one time it was 95 times, divided by 95 WB is 1 gram, I don't know, the molecular mass of its solute is 39 grams benzene and the molar mass of benzene is 78. If this goes two times from 39 then MB will come to 05/95, children. Meaning it can be written as 5/95. So this 95 * 2 / 5 will go from 5 to 19 times So two times 19 is 38 grams per mole. So the answer to this is understood first.

[00:23:51]This was a question on Colligative Property from the Solution Chapter.

[00:23:53]So this was your physical chemistry. Hope you did well as always in the paper.

[00:23:57]Thank you so much.