Question

The hydrogen ion concentration and pH of the solution made by mixing 100 mL of 1.0 M $HN{O}_3$ with 100 mL of 0.8 M $KOH$, are __________.

• A. $\left[H^{+}\right]=0.1,pH=1$
• B. $\left[H^{+}\right]=0.01,pH=2$
• C. $\left[H^{+}\right]=1\times {10}^{-12},pH=12$
• D. $\left[H^{+}\right]=1\times {10}^{-7},pH=7$

Answer 1

The correct option is A $\left[H^{+}\right]=0.1,pH=1$

As $HN{O}_3$ is a strong acid and $KOH$ is a strong base therefore, neutralisation reaction will take place.
$HN{O}_3+KOH\to KN{O}_3+H_{2}O$
As the equivalents of $HN{O}_3$ are more compared to $KOH$ final solution will be acidic.
$\left[H^{+}\right]=\frac{100\times 1-100\times 0.8}{100+100}=0.1M$
$pH=-log\left[H^{+}\right]=1$