Surface Chemistry JEE Main previous year questions with solutions

5 solved JEE Main questions on Surface Chemistry, free to read — no sign-in needed. The full chapter has 125 questions; sign in to attempt the remaining 120 in the exam simulator.

Answers checked against the official answer keys.

1. Q1JEE Main 2023 (13 Apr, Shift 2)
   Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : The diameter of colloidal particles in solution should not be much smaller than wavelength of light to show Tyndall effect. Reason R : The light scatters in all directions when the size of particles is large enough. In the light of the above statements, choose the correct answer from the options given below :
   1. A.Both A and R are correct but R is NOT the correct explanation of A
   2. B.A is true but R is false
   3. C.A is false but R is true
   4. D.Both A and R are correct and R is the correct explanation of A
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   Answer: (D)

   Conditions for Tyndall effect: (i) Diameter of colloidal particles in solution is not much smaller than wavelength of the light used. (ii) The refractive indices of the dispersed phase and dispersion medium differ greatly in magnitude. If size of particles is large enough than light scatters in all directions. So Both A and R are correct and R is the correct explanation of A.
2. Q2JEE Main 2022 (25 Jul, Shift 1)Carbon and Its Compounds
   Match List - I with List - II List-II List-II A ${N}_{2}\left(g\right)+3{H}_{2}\left(g\right)\rightarrow 2{NH}_{3}\left(g\right)$ I $Cu$ B $CO\left(g\right)+3{H}_{2}\left(g\right)\rightarrow {CH}_{4}\left(g\right)+{H}_{2}O\left(g\right)$ II $Cu/ZnO-{Cr}_{2}{O}_{3}$ C $CO\left(g\right)+{H}_{2}\left(g\right)\rightarrow HCHO\left(g\right)$ III ${Fe}_{x}{O}_{y}+{K}_{2}O+{Al}_{2}{O}_{3}$ D $CO\left(g\right)+2{H}_{2}\left(g\right)\rightarrow {CH}_{3}OH\left(g\right)$ IV $Ni$ Choose the correct answer from the options given below
   1. A.$\left(A\right)-\left(II\right),\left(B\right)-\left(IV\right),\left(C\right)-\left(I\right),\left(D\right)-\left(III\right)$
   2. B.$\left(A\right)-\left(II\right),\left(B\right)-\left(I\right),\left(C\right)-\left(IV\right),\left(D\right)-\left(III\right)$
   3. C.$\left(A\right)-\left(III\right),\left(B\right)-\left(IV\right),\left(C\right)-\left(I\right),\left(D\right)-\left(II\right)$
   4. D.$\left(A\right)-\left(III\right),\left(B\right)-\left(I\right),\left(C\right)-\left(IV\right),\left(D\right)-\left(II\right)$
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   Answer: (C)

   List-II List-II A ${N}_{2}\left(g\right)+3{H}_{2}\left(g\right)\rightarrow 2{NH}_{3}\left(g\right)$ III ${Fe}_{x}{O}_{y}+{K}_{2}O+{Al}_{2}{O}_{3}$ B $CO\left(g\right)+3{H}_{2}\left(g\right)\rightarrow {CH}_{4}\left(g\right)+{H}_{2}O\left(g\right)$ IV $Ni$ C $CO\left(g\right)+{H}_{2}\left(g\right)\rightarrow HCHO\left(g\right)$ I $Cu$ D $CO\left(g\right)+2{H}_{2}\left(g\right)\rightarrow {CH}_{3}OH\left(g\right)$ II $Cu/ZnO-{Cr}_{2}{O}_{3}$ ${N}_{2}\left(g\right)+3{H}_{2}\left(g\right)\rightarrow 2{NH}_{3}\left(g\right)$ is Haber process and catalyst used are ${Fe}_{x}{O}_{y}+{K}_{2}O+{Al}_{2}{O}_{3}$. ${H}_{2}O+C\rightarrow {H}_{2}+CO$ The product of this is called synthesis gas and can be extremely useful in bonding with metallic heterogeneous catalysts to produce different organic compounds.
3. Q3JEE Main 2020 (08 Jan, Shift 2)Disaccharides and Polysaccharides
   For the following Assertion and Reason, the correct option is: Assertion: For hydrogenation reactions, the catalytic activity increases from Group $5$ to Group $11$ metals with maximum activity shown by Group $7-9$ elements. Reason: The reactants are most strongly adsorbed on group $7-9$ elements.
   1. A.The assertion is true, but the reason is false
   2. B.Both assertion and reason are false
   3. C.Both assertion and reason are true and the reason is the correct explanation for the assertion
   4. D.Both assertion and reason are true but the reason is not the correct explanation for the assertion
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   Answer: (A)

   The general trend for the activity for hydrogenation increases from left to right. In Hydrogenation reaction, catalytic activity depends on variable oxidation states as well as atomic size. Hence for hydrogenation reactions, the catalytic activity increases from a group 5 to group 11 metals with maximum activity shown by group 7-9 elements.
4. Q4JEE Main 2023 (13 Apr, Shift 1)
   What happens when a lyophilic sol is added to a lyophobic sol?
   1. A.Film of lyophilic sol is formed over lyophobic sol
   2. B.Lyophilic sol is dispersed in lyophobic sol
   3. C.Film of lyophobic sol is formed over lyophilic sol
   4. D.Lyophobic sol is coagulated
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   Answer: (A)

   Film of lyophilic sol is formed over lyophobic sol as lyophilic sol acts as a protective colloid. Lyophobic solutions are unstable in nature. When a lyophilic sol is added to lyophobic sol, stability of lyophobic sol increases due to a protective film of lyophilic sol present over the lyophobic sol.
5. Q5JEE Main 2023 (12 Apr, Shift 1)
   Four gases, $A,B,C$ and $D$ have critical temperatures $5.3,33.2,126.0$ and $154.3K$ respectively For their adsorption on a fixed amount of charcoal, the correct order is :
   1. A.$C\gt D\gt B\gt A$
   2. B.$C\gt B\gt D\gt A$
   3. C.$D\gt C\gt B\gt A$
   4. D.$D\gt C\gt A\gt B$
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   Answer: (C)

   Critical temperature of a gas is the temperature at or above which vapor of the gas cannot be liquefied, no matter how much pressure is applied. The extent of adsorption is directly proportional to the critical temperature of the gas. Higher is the critical temperature of the gas, greater is the extent of adsorption. Order of ${T}_{c}D\gt C\gt B\gt A$ Order of adsorption $D\gt C\gt B\gt A$