Exam

NTA Abhyas

Year

2020

Subject

Chemistry

Chapter

Ionic Equilibrium

NTA Abhyas 2020 · Chemistry · Ionic Equilibrium

1M NH _ 4 OH and 1MHCl are mixed to make a total volume of 300mL ....

$1M{NH}_{4}OH$ and $1MHCl$ are mixed to make a total volume of $300mL$. If $pH$ of the mixture is $9.26$ and $p{K}_{a}\left(N{H}_{4}^{+}\right) = 9.26$ then what would be the volume ratio of ${NH}_{4}OH$ and $HCl$.

Step-by-step solution

$pOH = 14 - pH = p{K}_{b} + log \dfrac{x}{300 - 2x}$
$= 14 - 9.26 = - \log \left({10}^{- 4.74}\right) + log \dfrac{x}{300 - 2x}$
$⇒ \dfrac{x}{300 - 2x} = 1$
$⇒ 300 = 3x ⇒ x = 100mL$
\dfrac{{V}_{{\text{NH}_{4} \text{OH}}}{{V}_{\text{HCl}}} \text{=}\text{2}