AP EAMCET · Chemistry · Surface Chemistry

Which of the following statements is not correct?

A Both physical and chemical adsorptions are exothermic
B Physical adsorption takes place with decrease of free energy whereas chemical adsorption occurs with increase of free energy
C Physical adsorption requires low activation energy but chemical adsorption requires high activation energy
D The magnitude of chemical adsorption increases and that of physical adsorption decreases with rise in temperature

Verified Solution

Answer & Solution

Correct Answer

(B) Physical adsorption takes place with decrease of free energy whereas chemical adsorption occurs with increase of free energy

Step-by-step Solution

Detailed explanation

Both physical and chemical adsorption are exothermic in nature. But, chemical absorption requires high heat of adsorption due to formation of chemical bond. Moreover, magnitude of chemical adsorption increases and that of physical adsorption decreases with the rise in…

Apply the relevant identity from the chapter and substitute the values established in the previous step, keeping the original constraint in view.

Use the simplified expression to isolate the unknown, then plug the result back into the question setup to confirm the working is internally consistent.

Cross-check against a boundary or limiting case. Both the dimensional balance and the qualitative behaviour at the extreme should agree with the candidate answer.

Combine the steps above to identify the correct option. The remaining choices each fail at least one of the consistency, dimensional, or boundary checks.

Same subject

Match the following.

List - $I$ Reaction		List - $II$ Catalyst
$(A)$	$N_{2} (g) + 3 H_{2} (g) ⟶ 2 {NH}_{3} (g)$	$(I)$	$Ni$
$(B)$	$2 H_{2} (g) + O_{2} (g) ⟶ 2 H_{2} O (l)$	$(II)$	$Pt$
$(C)$	$CO (g) + 3 H_{2} (g) ⟶ {CH}_{4} (g) + H_{2} O (g)$	$(III)$	$ZnO - {Cr}_{2} O_{3}$
$(D)$	$CO (g) + 2 H_{2} (g) ⟶ {CH}_{3} OH (g)$	$(IV)$	$Fe$

The correct answer is:

AP EAMCET 2019 Easy

List-I (aquated ion)	List-II (colour)
A)	\(\mathrm{Ni}^{2+}\)	I)	violet
B)	\(\mathrm{Fe}^{3+}\)	II)	blue
C)	\(\mathrm{Mn}^{3+}\)	III)	yellow
D)	\(\mathrm{V}^{4+}\)	IV)	red
		V)	green

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