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The $pK_b$ of dimethylamine and $pK_a$ of acetic acid are 3.27 and 4.77 respectively at $T$(K). The correct option for the pH of dimethylammonium acetate solution is:
A
5.50
B
7.75
C
6.25
D
8.50
Detailed Solution
Dimethylammonium acetate is a salt of a weak acid and a weak base:
$pH = 7 + \frac{1}{2}pK_a - \frac{1}{2}pK_b$
$= 7 + \frac{1}{2}(4.77) - \frac{1}{2}(3.27) = 7 + 0.75 = 7.75$