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JEE Main

Explore popular questions from Surface Chemistry for JEE Main. This collection covers Surface Chemistry previous year JEE Main questions hand picked by experienced teachers.

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Q 1. The formation of micelles(Associated colloids) takes place

A

above {tex} \mathrm { CMC } {/tex} and at kraft temperature.

B

at {tex}\mathrm{CMC}{/tex} and above kraft temperature.

C

at {tex} \mathrm{CMC}{/tex} and at kraft temperature.

above {tex} \mathrm{CMC}{/tex} and above kraft temperature.

Explanation

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Q 2. Which of the following is an example of positively charged sols?

A

{tex} \mathrm { As } _ { 2 } \mathrm { S } _ { 3 } {/tex}

B

Gold sol

C

Congo red sol

Haemoglobin

Explanation



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Q 3. When a graph is plotted between {tex} \mathrm { x } / \mathrm { m } {/tex} versus pressure at constant temperature. The Freundlich equation at 'B' is (if {tex} n /> 1 ) {/tex}

A

{tex} \frac { x } { m } = k P ^ { \infty } {/tex}

{tex} \frac { x } { m } = k P ^ { \frac { 1 } { n } } {/tex}

C

{tex} \frac { x } { m } = k P ^ { 1 } {/tex}

D

{tex} \frac { x } { m } = k P ^ { n } {/tex}

Explanation

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Q 4. Gelatin is added in manufacture of ice cream in order to

A

prevent formation of a colloid.

stabilise the colloid and prevent crystallisation.

C

cause the mixture to solidify easily.

D

improve flavour.

Explanation

Gelatin absorbs free water in the ice cream and prevent the formation of large crystals.

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Q 5. Which of the following statement is incorrect?

A

Lyophilic sols are reversible.

B

Lyophilic sols are more stable than lyophobic sols.

C

Lyophobic sols require stabilising agent for their preservation.

Lyophobic sols can be formed by direct mixing of dispersed phase and dispersion medium.

Explanation





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Q 6. Which of the following graph represents the variation of amount of chemisorptions of a gas by a solid with temperature under constant pressure?

A

B

D

Explanation





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Q 7. The colloidal sols are purified by

A

Peptisation

B

Coagulation

Dialysis

D

None of these

Explanation

Colloids are purified by dialysis. Dialysis is the process of removing a dissolved substance from the colloidal solution by means of diffusion through a suitable membrane (parchment membrane or animal membrane)

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Q 8. Which of the following is not heterogeneous?

A

Emulsion

True solution

C

Suspension

D

Colloidal solution

Explanation

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Q 9. Cellulose dispersed in ethanol is called

A

emulsion

B

micelle

collodion

D

hydrophilic solution

Explanation

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Q 10. According to the adsorption theory of catalysis, the speed of reaction increases because

adsorption lowers the activation energy of the reaction.

B

the concentration of reactant molecules at the active centres of the catalyst becomes high due to adsorption.

C

in the process of adsorption, the activation energy of the molecules becomes large.

D

adsorption produces heat which increases the speed of the reaction.

Explanation

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Q 11. Which one of the following characteristics is not correct for physical adsorption?

A

Adsorption on solids is reversible.

Adsorption decreases with increase in temperature.

C

Adsorption is spontaneous.

D

Both enthalpy and entropy of adsorption are negative.

Explanation

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Q 12. Identify the gas which is readily adsorbed by activated charcoal.

A

{tex} \mathrm { N } _ { 2 } {/tex}

{tex} \mathrm { SO } _ { 2 } {/tex}

C

{tex} \mathrm { H } _ { 2 } {/tex}

D

{tex} \mathrm { O } _ { 2 } {/tex}

Explanation

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Q 13. The concentration of electrolyte required to coagulate a given amount of {tex} \mathrm { As } _ { 2 } \mathrm { S } _ { 3 } {/tex} sol is minimum in case of

A

{tex} \mathrm { K } _ { 2 } \mathrm { SO } _ { 4 } {/tex}

{tex} \mathrm { Al } \left( \mathrm { NO } _ { 3 } \right) _ { 3 } {/tex}

C

{tex} \operatorname { Mg } \left( \mathrm { NO } _ { 3 } \right) {/tex}

D

{tex} \mathrm { KNO } _ { 3 } {/tex}

Explanation

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Q 14. Plot of {tex} \log x / m {/tex} against {tex} \log p {/tex} is a straight line inclined at an angle of {tex} 45 ^ { \circ } . {/tex} When the pressure is 4 atm and Freundlich parameter, {tex} k {/tex} is 10 , the amount of solute adsorbed per gram of adsorbent will be {tex} ( \log 5 = 0.6990 ) {/tex}

A

2{tex} g {/tex}

B

4{tex} g {/tex}

C

16{tex} g {/tex}

40{tex} g {/tex}

Explanation



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Q 15. Which one of the following is an example for homogeneous catalysis?

A

Manufacture of sulphuric acid by contact process.

B

Manufacture of ammonia by Haber's process.

Hydrolysis of sucrose in presence of dilute hydrochloric acid.

D

Hydrogenation of oil.

Explanation



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Q 16. The efficiency of enzyme catalysis is due to its capacity to

A

form a strong enzyme-substrate complex.

B

change the shape of the substrate.

lower the activation energy of the reaction.

D

form a colloidal solution in water.

Explanation

The efficiency of enzyme catalysis is due to its capacity to lower the activation energy of the reaction.

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Q 17. Which of the following electrolytes is least effective in coagulating ferric hydroxide solution?

{tex} \mathrm { KNO } _ { 3 } {/tex}

B

{tex} \mathrm { K } _ { 2 } \mathrm { SO } _ { 4 } {/tex}

C

{tex} \mathrm { K } _ { 2 } \mathrm { Cr } _ { 2 } \mathrm { O } _ { 7 } {/tex}

D

{tex} \mathrm { K } _ { 4 } \left[ \mathrm { Fe } ( \mathrm { CN } ) _ { 6 } \right] {/tex}

Explanation

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Q 18. Example of intrinsic colloid is

glue

B

sulplur

C

{tex} \mathrm { Fe } {/tex}

D

{tex} \mathrm { As } _ { 2 } \mathrm { S } _ { 3 } {/tex}

Explanation