JEE Main 2022 · 25 Jun · Shift 2 · Chemistry Q68

ChemistrySingle correct+4 / -1Question 68 of 90

Given below are two statements one is labelled as Assertion A and the other is labelled as Reason R :

Assertion A : The amphoteric nature of water is explained by using Lewis acid/base concept.

Reason R : Water acts as an acid with $\mathrm{NH_3}$ and as a base with $\mathrm{H_2S}$ .

In the light of the above statements choose the correct answer from the options given below :

Both A and R are true and R is the correct explanation of A.

Both A and R are true but R is NOT the correct explanation of A.

A is true but R is false.

A is false but R is true.

Answer and worked solution

Official answer: D

Assertion is false: water's amphoteric behaviour is explained by the Brønsted-Lowry (proton) concept, not the Lewis concept.

Reason is true: $\mathrm{H_2O+NH_3\rightarrow OH^-+NH_4^+}$ (acid) and $\mathrm{H_2O+H_2S\rightarrow H_3O^++HS^-}$ (base).

(D)

Topics:Acids and bases

JEE Main 2022 · 25 Jun · Shift 2, Chemistry question 68