Question

A $50mL$ solution of $pH=1$ is mixed with a $50mL$ solution of $pH=2$, then $pH$ of the mixture will be nearly

• A. 0.76
• B. 1.26
• C. 1.76
• D. 2.26

Answer 1

Answer: (B)

1.26

For $pH=1$, $\left[H^{+}\right]=0.1$

For $pH=2$, $\left[H^{+}\right]=0.01$

$V=50$ for both
$\left[H^{+}\right]$ of mixture is $=\frac{M_1{V}_1+M_2{V}_2}{V_1+V_2}\Rightarrow \frac{50(0.1+0.01)}{100}$
$\left[H^{+}\right]\Rightarrow \frac{0.11}{2}\Rightarrow 0.055$

$pH=-log0.055=1.26$