---
title: "A student prepares a \\(1.0\\text{ L}\\) buffer solution containing \\(0.050\\text{ mol}\\) of a weak monoprotic acid \\(\\text{HA}\\) (\\(K_a = 1.0 \\times 10^{-4}\\)) and \\(1.05\\text{ mol}\\) of \\(\\text{NaA}\\). To this solution, the student adds \\(0.050\\text{ mol}\\) of \\(\\text{HCl(g)}\\), which dissolves completely without changing the volume of the solution. Assuming the temperature is \\(298\\text{ K}\\), what is the \\(\\text{pH}\\) of the resulting solution?"
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url: "https://nerd-notes.com/ubq/121522/"
date_modified: "2026-08-23T05:05:01+00:00"
---

# A student prepares a \(1.0\text{ L}\) buffer solution containing \(0.050\text{ mol}\) of a weak monoprotic acid \(\text{HA}\) (\(K_a = 1.0 \times 10^{-4}\)) and \(1.05\text{ mol}\) of \(\text{NaA}\). To this solution, the student adds \(0.050\text{ mol}\) of \(\text{HCl(g)}\), which dissolves completely without changing the volume of the solution. Assuming the temperature is \(298\text{ K}\), what is the \(\text{pH}\) of the resulting solution?

A student prepares a \(1.0\text{ L}\) buffer solution containing \(0.050\text{ mol}\) of a weak monoprotic acid \(\text{HA}\) (\(K_a = 1.0 \times 10^{-4}\)) and \(1.05\text{ mol}\) of \(\text{NaA}\). To this solution, the student adds \(0.050\text{ mol}\) of \(\text{HCl(g)}\), which dissolves completely without changing the volume of the solution. Assuming the temperature is \(298\text{ K}\), what is the \(\text{pH}\) of the resulting solution?

- **A.** \(1.30\)
- **B.** \(3.00\)
- **C.** \(4.00\)
- **D.** \(5.00\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121522/*