Weak Acid and Base Equilibria Practice Test

Two separate $0.10,\text{M}$ solutions are prepared at $25^\circ\text{C}$: one of acetic acid, $\text{HC}_2\text{H}_3\text{O}_2$, with $K_a=1.8\times10^{-5}$, and one of hydrocyanic acid, HCN, with $K_a=6.2\times10^{-10}$. After equilibrium is established in each solution, which statement is correct?

A $0.10,\text{M}$ solution of acetic acid, $\text{CH}_3\text{COOH}(aq)$, is prepared at $25^\circ\text{C}$. The equilibrium is $\text{CH}_3\text{COOH}(aq)\rightleftharpoons \text{H}^+(aq)+\text{CH}_3\text{COO}^-(aq)$ with $K_a=1.8\times10^{-5}$. Which statement about concentrations at equilibrium is correct (neglecting the autoionization of water)?