Question

Four grams of NaOH solid are dissolved in just enough water to make 1 litre of solution.What is the $\left[H^{+}\right]$ of the solution in moles/litre?

• A. ${10}^{-2}$
• B. ${10}^{-1}$
• C. ${10}^{-12}$
• D. ${10}^{-13}$

Answer 1

Answer: (D)

${10}^{-13}$

Mass of $NaOH=4$ $g$

Number of Moles$=\frac{4}{40}=0.1$

Molarity$=0.1M$

$\left[O{H}^{-}\right]=0.1M$

$\left[H^{+}\right]=\frac{K_w}{\left[O{H}^{-}\right]}$

$\left[H^{+}\right]={10}^{-13}M$