The dissociation constant of propionic acid i | vedclass

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(B) For a weak acid,the dissociation constant $K_a$ is related to the degree of dissociation $\alpha$ and concentration $C$ by the formula: $K_a = C\a

Vedclass · Accepted Answer

$1.61 	imes 10^{-2}$

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(B) For a weak acid,the dissociation constant $K_a$ is related to the degree of dissociation $\alpha$ and concentration $C$ by the formula: $K_a = C\alpha^2$ (assuming $\alpha \ll 1$).Given $K_a = 1.32 	imes 10^{-5}$ and $C = 0.05 \ M$.$\alpha = \sqrt{\frac{K_a}{C}}$$\alpha = \sqrt{\frac{1.32 	imes 10^{-5}}{0.05}}$$\alpha = \sqrt{\frac{1.32 	imes 10^{-5}}{5 	imes 10^{-2}}} = \sqrt{0.264 	imes 10^{-3}} = \sqrt{2.64 	imes 10^{-4}}$$\alpha = 1.624 	imes 10^{-2} \approx 1.61 	imes 10^{-2}$.

The dissociation constant of propionic acid is $1.32 \times 10^{-5}$. Calculate the degree of dissociation of the acid in a $0.05 \ M$ solution.

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