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AP EAMCET · Chemistry · Ionic Equilibrium

If the \(\mathrm{p} K_a\) of acetic acid and \(\mathrm{p} K_b\) of dimethylamine are 4.76 and 3.26 respectively, the \(\mathrm{pH}\) of dimethyl ammonium acetate solution is

  1. A 7.75
  2. B 6.75
  3. C 7
  4. D 8.5
Verified Solution

Answer & Solution

Correct Answer

(A) 7.75

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \text { } \begin{aligned} \mathrm{pH}= & 7+\frac{1}{2}\left[\mathrm{p} K_a-\mathrm{p} K_b\right] \\ \text { Here, } \mathrm{p}_a & =4.76, \mathrm{p} K_b=3.26 \\ & =7+\frac{1}{2}[4.76-3.26] \\ & =7+\frac{1}{2}[1.50] \\ & =7+0.75=7.75\end{aligned}\end{aligned}\)