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 :

1. 8.50

2. 5.50

3. 7.75

4. 6.25

Doubtly Asked 30 Oct 2026 NEET UG 2021 Practice test neet Save WhatsApp Report

1 answer

Best answer

Answer: 3. 7.75

Key idea: for a salt of a weak acid and a weak base, \(\mathrm{pH}=7+\tfrac12(\mathrm{p}K_a-\mathrm{p}K_b)\).

\(\mathrm{pH}=7+\tfrac12(4.77-3.27)=7+0.75=7.75\).

Doubtly AI · 30 Oct 2026 AI-generated · not yet verified Report

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