Question

Calculate $pH$ of the (write the value to the nearest integer) Decimolar solution of Baryta $\left(Ba{\left(OH\right)}_2\right)$

• A. $2.70$
• B. $5.70$
• C. $9.90$
• D. $11.30$

Answer 1

Answer: (D)

$11.30$

The solution is decimolar.
Hence, $C$=$0.1M$
It is diluted 100 times,so,

$C$=$\frac{0.1}{100}$=${10}^{-3}mol/d{m}^3$

=n \alpha C$

where,

n=2

$\therefore \left[O{H}^{-}\right]=2\times 1\times {10}^{-3}=2\times {10}^{-3}mol/d{m}^3$
$pOH=-lo{g}_{10}\left[O{H}^{-}\right]=-lo{g}_{10}(2\times {10}^{-3})=3-0.301=2.699$
$pH=14-pOH=14-2.699=11.301$

Hence, the correct option is $\left(D\right)$.