Ionic EquilibriumHard
Question
Which of the following mixture gives a buffer solution with $pH = 9.25$ ?
Given : ${pK}_{b}\left( {NH}_{4}OH \right) = 4.75$
Options
A.$0.2M{NH}_{4}OH(0.4\text{ }L) + 0.1MHCl(1\text{ }L)$
B.$0.2M{NH}_{4}OH(0.5\text{ }L) + 0.1MHCl(0.5\text{ }L)$
C.$0.5M{NH}_{4}OH(0.2\text{ }L) + 0.2MHCl(0.5\text{ }L)$
D.$0.4M{NH}_{4}OH(1\text{ }L) + 0.1MHCl(1\text{ }L)$
Solution
$pOH = {pK}_{b} + log\frac{\text{~Salt~}}{\text{~Base~}}$
$$4.75 = 4.75 + log\frac{\text{~Salt~}}{\text{~Base~}} $$Milimoles of [Salt] = milimoles of [Base]
Option (D) :
$$\begin{matrix} & {NH}_{4}OH + HCl \rightarrow {NH}_{4}Cl + H_{2}O \\ & 0.2M,0.5\text{ }L\ 0.1M,0.5\text{ }L \\ & 100\text{~}\text{mmole}\text{~}\ 50\text{~}\text{mmole}\text{~} \\ & 50\text{~}\text{mmole}\text{~}\ - \ 50\text{~}\text{mmole}\text{~} \\ & \text{~}\text{Milimoles of}\text{~}{NH}_{4}OH = \text{~}\text{milimoles of}\text{~}{NH}_{4}Cl \end{matrix}$$
Create a free account to view solution
View Solution FreeMore Ionic Equilibrium Questions
Equimolar solutions of the following substances were prepared separately. Which one of these will record the highest pH ...If the equilibrium constant for the reaction of weak acid HA with strong base is 109, then pH of 0.1 M Na A is...pH of a 0.1 M monobasic acid is found to be 2. Hence its osmotic pressure at a given temperature TK is :-...How much water must be added to 300 ml of 0.2 M solution of CH3COOH for the degree of dissociation of the acid to double...The pH of an acidic buffer mixture is:...