Question

Given the following acids and their Ka values: Phenol, C6H5OH Ka = 1.00 × 10-10 Acetic acid, CH3CO2H Ka = 1.80 × 10-5 Nitrous acid, HNO2 Ka = 4.50 × 10-4 What is the order of increasing base strength for C6H5O−, CH3COO−, and NO2−? Group of answer choices

Answer 1

Answer:

$NO_2^-$ < $CH_3COO^-$ < $C_6H_5O^-$

Explanation:

$K_a$ value is a measure of acidic strength. The larger the $K_a$ value, the stronger is the acid and the weaker is the conjugate base.

The given $K_a$ values are as follows -

Phenol = $1\times 10^-^1^0$

Acetic acid = $1.80 \times 10^-^5$

Nitrous acid = $4.50 \times 10^-^4$

Order of increasing acid strength will be -

Phenol < Acetic acid < Nitrous acid

Strongest acid will have weakest conjugate base so the order of increasing base strength will be -

$NO_2^-$ < $CH_3COO^-$ < $C_6H_5O^-$