Q28 / 180 · KCET 2007 · Chemistry
Hydroxyl ion concentration of $10^{-2} \mathrm{M} \mathrm{HCl}$ is
- A$1 \times 10^{1} \mathrm{~mol} \mathrm{dm}^{-3}$
- Correct answerB$1 \times 10^{-12} \mathrm{~mol} \mathrm{dm}^{-3}$
- C$1 \times 10^{-1} \mathrm{~mol} \mathrm{dm}^{-3}$
- D$1 \times 10^{-14} \mathrm{~mol} \mathrm{dm}^{-3}$
Solution
$\left[\mathrm{H}^{+}\right]\left[\mathrm{OH}^{-}\right]=10^{-14}$
$$
\begin{aligned}
{\left[10^{-2}\right]\left[\mathrm{OH}^{-}\right] } &=10^{-14} \\
{\left[\mathrm{OH}^{-}\right] } &=\frac{10^{-14}}{10^{-2}}=10^{-12} \mathrm{~mol} \mathrm{dm}
\end{aligned}
$$
Hence, the correct answer is option: 'B'.