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Chemistry · EQUILIBRIUM
हिन्दीAn aqueous buffer solution contains 0.25 M \( \text{NH}_4\text{Cl} \) and 0.10 M \( \text{NH}_3 \). If the dissociation constant of ammonia is \( K_b = 1.80 \times 10^{-5} \) and \( K_w = 1.0 \times 10^{-14} \), the hydrogen ion concentration \( [\text{H}^+] \) in the solution is:
Correct answer · Option 1
\( 1.39 \times 10^{-9}\text{ M} \)
Explanation
\( [\text{OH}^-] = K_b \times \frac{[\text{NH}_3]}{[\text{NH}_4^+]} = 1.80 \times 10^{-5} \times \frac{0.10}{0.25} = 7.20 \times 10^{-6}\text{ M} \). Therefore, \( [\text{H}^+] = \frac{1.0 \times 10^{-14}}{7.20 \times 10^{-6}} = 1.39 \times 10^{-9}\text{ M} \).
