Question

Select correct statements(s):

• A. Acidic strength of HBr > HCl but reverse is true for their reducing property
• B. Basic strength of PH₃ > AsH₃ but reverse is true for their bond angle
• C. Dipole moment of CH₃Cl > CH₃F but reverse is true for their $\text{H} \hat{\text{C}} \text{H}$ bond angle
• D. $\text{K}_{\text{a}_{1}}$ of fumaric acid is higher than maleic acid but reverse is true for their $\text{K}_{\text{a}_{2}}$

Answer 1

Answer: (C)

(a) Acidic sterngth of HBr > HCl and their reducing proeprties are also in same order.
(b) Basic strength of PH₃ > AsH₃, their bond angles are also in same order

(c) $\theta_{2} > \theta_{1}$ because bond pair in C-F is held more close to F atom than bond pair in C-Cl bond. B.P - B.P repulsion less in CH₃F i.e. $\text{H} \hat{\text{C}} \text{H}$ bond angle is more.

(d) $\text{K}_{\text{a}_{1}}$ of maleic acid is higher than $\text{K}_{\text{a}_{1}}$ of fumaric acid but reverse is true for their $\text{K}_{\text{a}_{2}}$ .

In maleic acid after loosing H⁺ ion intramolecular hydrogen bonding taking place so, H⁺ removal is easy hence, k_a1 will be higher for maleic acid