The $K_b$ of $NH_4OH$ is $1.8 \times 10^{-5}$. Calculate the $pH$ of a solution containing $0.15 \ M$ $NH_4OH$ and $0.25 \ M$ $NH_4Cl$.
(A) For a basic buffer solution,the $pOH$ is calculated using the Henderson-Hasselbalch equation: $pOH = pK_b + \log \frac{[Salt]}{[Base]}$.
Given: $K_b = 1.8 \times 10^{-5}$,$[Base] = 0.15 \ M$,$[Salt] = 0.25 \ M$.
$pK_b = -\log(1.8 \times 10^{-5}) = 5 - \log(1.8) = 5 - 0.255 = 4.745$.
$pOH = 4.745 + \log \frac{0.25}{0.15} = 4.745 + \log(1.667) = 4.745 + 0.222 = 4.967$.
Since $pH + pOH = 14$,$pH = 14 - 4.967 = 9.033$.
Given: $K_b = 1.8 \times 10^{-5}$,$[Base] = 0.15 \ M$,$[Salt] = 0.25 \ M$.
$pK_b = -\log(1.8 \times 10^{-5}) = 5 - \log(1.8) = 5 - 0.255 = 4.745$.
$pOH = 4.745 + \log \frac{0.25}{0.15} = 4.745 + \log(1.667) = 4.745 + 0.222 = 4.967$.
Since $pH + pOH = 14$,$pH = 14 - 4.967 = 9.033$.
Explore More
Similar Questions
To obtain a buffer which should be suitable for maintaining a $pH$ of about $4 - 5$,we need to have in solution,a mixture of
Difficult
View Solution$A$ buffer solution is prepared by mixing equimolar acetic acid and sodium acetate. If $K_{a}$ of acetic acid is $1.78 \times 10^{-5}$,find the $pH$ of the buffer solution.
Find $pH$ of the resultant solution formed by the addition of $500 \ mL$ $0.1 \ M$ $Ba(OH)_2$ and $500 \ mL$ $0.6 \ M$ $NH_4Cl$ in $1 \ L$ pure $H_2O$ at $25 \ ^oC$ (Use $log \ 2 = 0.3$,$log \ 3 = 0.5$,$log \ 5 = 0.7$,$K_b(NH_3) = 10^{-5}$)
Difficult
View SolutionWhich one of the following is not a buffer solution?
MediumAIIMS 2003
View SolutionThe $[HCO_{3}^{-}]/[H_{2}CO_{3}]$ ratio in the buffer present in blood $(pH = 7.4)$ is approximately $(pK_{a} = 6.1$ for $H_{2}CO_{3})$.
Medium
View SolutionVedclass Products
For Students
Vedclass Test Series
Mock tests in real JEE/NEET style with performance analysis. 5-day free trial.
Start Free TrialFor Teachers
Exam Paper Generator
Generate Set A/B/C/D exam papers from 7.5L+ questions in 2 minutes. 3 chapters free.
Try FreeFor Institutes
Online Exam Module
Live online exams with unlimited students, 360° analytics & white-label branding.
See Demo