Question

$25ml,0.2MCa(OH{)}_2$ is neutralised by $10ml$ of $1MHCl$. The $pH$ of resulting solution is:

• A. $1.37$
• B. $9$
• C. $12$
• D. $7$

Answer 1

The correct option is D $7$

$25mLof0.2MCa(OH{)}_2+10mLof1MHCL$

Moles of $H_3{O}^{+}=\frac{10\times 1}{1000}=0.01mol$

Moles of $O{H}^{-}=\frac{25\times 0.2\times 2}{1000}=0.01mol$

Since two solutions have equal moles of $H_3{O}^{+}$ and $O{H}^{-}$, therefore the two solutions get completely neutralised and $pH=7$