The pH of a 0.01 M weak acid $\mathrm{HX}\left(\mathrm{K}_{\mathrm{a}}=4 imes 10^{-10} ight)$ is found to be 5. Now the acid solution is diluted with excess of water so that the pH of the solution changes to 6. The new concentration of the diluted weak acid is given as $x imes 10^{-4}…

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The pH of a 0.01 M weak acid $\mathrm{HX}\left(\mathrm{K}_{\mathrm{a}}=4 	imes 10^{-10}ight)$ is found to be 5. Now the acid solution is diluted with excess of water so that the pH of the solution changes to 6. The new concentration of the diluted weak acid is given as $x 	imes 10^{-4} \mathrm{M}$. The value of x is ________ (nearest integer)

Aicharya · Accepted Answer

$\begin{aligned} & \mathrm{H}^{+}=\sqrt{\mathrm{K}_a \times \mathrm{C}} \ & 10^{-6}=\sqrt{4 \times 10^{-10} \times \mathrm{C}} \ & 10^{-12}=4 \times 10^{-10} \times \mathrm{C} \ & \mathrm{C}=\frac{1}{4} \times 10^{-2}=0.25 \times 10^{-2}=25 \times 10^{-4}\end{aligned}$

The pH of a 0.01 M weak acid $\mathrm{HX}\left(\mathrm{K}_{\mathrm{a}}=4 \times 10^{-10}\right)$ is found to…

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