Question

The $pH$ of a mixture of $10$ml of $0.1$M $H_{2}S{O}_4$, $5$ml of $0.2$N $HCl$ and $5$ml of $0.1$M $Ca(OH{)}_2$ is:

• A. $1.3$
• B. $0.5$
• C. $0$
• D. $1.5$

Answer 1

Answer: (A)

$1.3$

Mixture is acidic. Sulphuric acid will completely neutralize calcium hydroxide.

$HCl$ will remain unneutralized.

$\left[H^{+}\right]$ left after neutralization will be equal to $\left[H^{+}\right]$ from $HCl$

$\left[H^{+}\right]$ left after neutralization:

$\left[H^{+}\right]=\frac{0.2\times 5}{20}=0.05M$

$pH$$=-log\left(0.05\right)=1.3$