Question

$100mL$ of $0.2NNaOH$ is mixed with $100mL0.1NHCl$ and the solution is made $1L$. The $pH$ of the solution is

• A. $4$
• B. $8$
• C. $10$
• D. $12.7$

Answer 1

Answer: (D)

$12.7$

$n{h}^{+}taken=\frac{100\times 0.1}{1000}=0.01$

$nO{H}^{-}taken=\frac{100\times 0.2}{1000}=0.02$

$H^{+}+O{n}^{-}\to H_{2}O$

$0.010.02$

$\Rightarrow n^{+}$ distance comletelyand amount of $O{H}^{-}$ left is $0.02-0.01=0.01$

$\therefore \left[O{H}^{-}\right]final=\frac{0.01}{200}\times 1000=0.05$

$P^{OH}=-wj\left(0.05\right)$

$P^{On}=1.30$

$P^n+P^{OH}=14$

$P^H=13-1.30$

$P^H=12.70$