Question

Calculate the $H^{+}$ ion concentration in $0.10M$ acetic acid solution. Given that the dissociation constant of acetic acid in water is $1.8\times {10}^{-6}$.

Answer 1

Dissociation constant $=1.8\times {10}^{-6}$

lonc of acentic acid $=0.1M$

we know that,

Degree of dissociation $\left(\alpha \right)=\sqrt{\frac{Ka}{c}}$ & concentration of $H^{+}$ion $=c\alpha$

Therefore, ion of $H^{+}$ion $=c\times \sqrt{\frac{Ka}{c}}$

$\Rightarrow \sqrt{Ka\times c}$

$\Rightarrow \sqrt{1.8\times {10}^{-6}\times 0.1}$

$\Rightarrow \sqrt{1.8\times {10}^{-7}}\Rightarrow \sqrt{18\times {10}^{-8}}$

$\left[H^{+}\right]\Rightarrow 4.24\times {10}^{-4}M$