Which of the following mixture gives a buffer solution with pH = 9.25 ? Given : pK_b (NH_4OH) = 4.75

0.2M NH_4OH (0.4 L) + 0.1M HCl (1 L)
0.2M NH_4OH (0.5 L) + 0.1M HCl (0.5 L)
0.5M NH_4OH (0.2 L) + 0.2M HCl (0.5 L)
0.4M NH_4OH (1 L) + 0.1M HCl (1 L)

Correct answer: 0.2M NH_4OH (0.5 L) + 0.1M HCl (0.5 L)

Solution

This option creates a buffer solution by combining a weak base (NH4OH) with its conjugate acid (NH4Cl) in a ratio that maintains the desired pH of 9.25, as calculated using the Henderson-Hasselbalch equation.

Related JEE Main Chemistry questions

The solubility product constants of Ag$_2$CrO$_4$, AgCl, AgBr and AgI are $1.1\times10^{-12}$, $1.8\times10^{-10}$, $5.0\times10^{-13}$ and $8.3\times10^{-17}$, respectively. If AgNO$_3$ solution is added to a mixture containing equal amounts of NaCl, NaBr, NaI and Na$_2$CrO$_4$, which silver salt will begin to precipitate at the highest Ag$^+$ concentration, i.e. the last one to form?
Two sparingly soluble salts, MY and NY$_3$, each have the same solubility product constant, $K_{sp}=6.2\times10^{-13}$, at room temperature. Which of the following statements is correct for these two salts?
Given the equilibrium constants for these reactions: $\text{N}_2 + 3\text{H}_2 \rightleftharpoons 2\text{NH}_3$, $K_1$ $\text{N}_2 + \text{O}_2 \rightleftharpoons 2\text{NO}$, $K_2$ $\text{H}_2 + \tfrac12\text{O}_2 \rightleftharpoons \text{H}_2\text{O}$, $K_3$ What is the equilibrium constant $K$ for the reaction $2\text{NH}_3 + \tfrac52\text{O}_2 \rightleftharpoons 2\text{NO} + 3\text{H}_2\text{O}$?
In a saturated solution of Ag$_2$C$_2$O$_4$, the concentration of Ag$^+$ ions is $2.2\times10^{-4}\ \text{mol L}^{-1}$. The solubility product constant, $K_{sp}$, of Ag$_2$C$_2$O$_4$ is:
Which species can behave as both a Brønsted acid and a Brønsted base?
Select the correct statement: Polyphosphates are used as water-softening agents because they

⚔️ Practice JEE Main Chemistry free + battle 1v1 →