Question

What is the pH of the resulting solution when equal volumes of $0.1MNaOH$ and $0.01M$ $HCl$ are mixed ?

• A. 7.0
• B. 1.04
• C. 12.65
• D. 2.0

Answer 1

Answer: (C)

$N_1{V}_1-N_2{V}_2=N.V.$
$0.1\times 1-0.01\times 1=N\times 2$
$[O{H}^{-}]=N_R=\frac{0.09}{2}=0.045N$
$pOH=-log(0.045)=1.35$
$\therefore pH=14-pOH=14-1.35=12.65$