• # question_answer Ionization constant of acetic acid is $1.8\times {{10}^{-5}}.$The concentration of${{H}^{+}}$ions in 0.1 M solution is A) $1.8\times {{10}^{-3}}M$             B) $1.6\times {{10}^{-5}}M$C) $CaS{{O}_{4}}.{{H}_{2}}O$                  D) $MgS{{O}_{4}}.7{{H}_{2}}O$

$C{{H}_{3}}COOH$ionize as follows: $\underset{C(1-\alpha )}{\mathop{C{{H}_{3}}COOH}}\,\underset{C\alpha }{\mathop{C{{H}_{3}}CO{{O}^{-}}}}\,+\underset{C\alpha }{\mathop{{{H}_{3}}{{O}^{+}}}}\,$ $[{{H}_{3}}{{O}^{+}}]=C\alpha$ And $\alpha =\sqrt{\frac{{{K}_{a}}}{C}}$(for any weak electrolyte) $[{{H}_{3}}{{O}^{+}}]=\sqrt{K\alpha C}$ $=\sqrt{1.8\times {{10}^{-5}}\times 0.1}$ $=1.34\times {{10}^{-3}}M.$ Hence, the correct option is [d].