Question

The half life time for the following reaction are

(i) H⁺+ OH^–  → H₂O t_1/2 = 10–12 sec.

(ii) N₂O₅ (aq) + 328k → 2NO₂ (g) + 1/2 O₂ (g) t_1/2 = 89 min.

(iii) CH₃COOC₂H₅ (l) + H₂O (l) + H^-→ CH₃COOH(I) + C₂H₅ (l) t_1/2 = 1000 days

(iv) [Cr(H₂O)₆]³⁺ + I– (aq) →   [Cr(H₂O)₅ I]²⁺ + H₂O (l) t_1/2 = 2000 yr

which is (a) fast reaction (b) slow reaction (c) moderate rate reaction -

(A) i, iv, (ii, iii) 

(B) i, ii, (iii, iv) 

(C) i, iii, (iv, ii) 

(D) i, ii, (iv, iii)

Answer 1

Correct Option (A) i, iv, (ii, iii) 

Explanation: 

Half life time is a measure of rate of reaction. Shorter the half life time, faster is the reaction. Therefore, reaction (i) is reaction.

Reaction (iv) is slow reaction. and reactions (ii) and (iii) are moderate rate reactions.