Question

$H_3{O}^{+}$ concentration of a $0.100M$ acetic acid solution $(K_a=1.8\times {10}^{-5})$ is:

• A. $1.8\times {10}^{-5}$
• B. $1.8\times {10}^{-4}$
• C. $1.3\times {10}^{-2}$
• D. $1.3\times {10}^{-3}$
• E. $0.9\times {10}^{-3}$

Answer 1

The correct option is D $1.3\times {10}^{-3}$

$\because H^{+}=C\alpha =0.1\sqrt{\frac{Ka}{0.1}}\because {\alpha }^{2}c=Ka$

$H_3{O}^{+}=H^{+}={(0.1\times 1.8\times {10}^{-5})}^{1/2}=1.34\times {10}^{-3}$

Hence, the correct otpion is D.