What is the ratio of concentration of salt to concentration of weak acid in buffer solution to maintain its…

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. 1.5
  2. 10.0
  3. 5.0
  4. 8.5

Solution

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

Asked in: MHT CET 2024 (02 May Shift 1)

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