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MHT CET · Chemistry · Ionic Equilibrium

What is the ratio of concentration of salt to concentration of weak acid in buffer solution to maintain its pH value \(7.2\left(\mathrm{pK}_{\mathrm{a}}=6.2\right)\).

  1. A 1.5
  2. B 10
  3. C 5
  4. D 8.5
Verified Solution

Answer & Solution

Correct Answer

(B) 10

Step-by-step Solution

Detailed explanation

\(\begin{aligned} & \mathrm{pH}=\mathrm{pKa}+\log \frac{[\text { Salt }]}{[\text { Acid }]} \\ & 7.2=6.2+\log \frac{[\text { Salt }]}{[\text { Acid }]} \\ & 1=\log \frac{[\text { Salt }]}{[\text { Acid }]}=\log _{10} 10 \\ \therefore \quad & \frac{[\text { Salt }]}{[\text { Acid }]}=10\end{aligned}\)