Question

Equal volume of following solution are mixed, in which case the $pH$ of resulting solution will be average value of $pH$ two solution.

• A. $pH=2HCI\&pH=12NaOH$
• B. $pH=2HCI\&pH=4HCI$
• C. $pH=2HCN\&pH=12NaOH{k}_a$ of $HCN={10}^{-10}$
• D. $pH=5C{H}_{3}COOH\&pH=9N{H}_3\left(aq\right)K_a\left(C{H}_{3}COOH\right)=K_b\left(N{H}_3\right)\left(aq\right)$

Answer 1

The correct option is A $pH=2HCI\&pH=12NaOH$

$pH=2,pOH=12$

$\downarrow$ $\downarrow$

$HCl$ $NaOH\Rightarrow pH=14-12=2$

$pH=\frac{p{H}_1+p{H}_2}{2}=\frac{2+2}{2}=2$ .