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title: "The acid-base indicator bromocresol green is a weak acid that dissociates in aqueous solution according to the equilibrium below.  \\[ \\text{HIn}\\text{(aq)} + \\text{H}_2\\text{O}\\text{(l)} \\rightleftharpoons \\text{H}_3\\text{O}^+\\text{(aq)} + \\text{In}^-\\text{(aq)} \\quad\\quad K_a = 1.0 \\times 10^{-5} \\text{ at } 25\\text{ }^\\circ\\text{C} \\]  In this system, \\(\\text{HIn}\\text{(aq)}\\) is yellow and \\(\\text{In}^-\\text{(aq)}\\) is blue. A student adds a few drops of bromocresol green to a buffer solution with a \\(\\text{pH}\\) of \\(3.50\\) at \\(25\\text{ }^\\circ\\text{C}\\). Which of the following correctly identifies the predominant form of the indicator in the buffer solution and the observed color of the solution?"
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url: "https://nerd-notes.com/ubq/123768/"
date_modified: "2026-09-28T12:30:14+00:00"
---

# The acid-base indicator bromocresol green is a weak acid that dissociates in aqueous solution according to the equilibrium below.

\[ \text{HIn}\text{(aq)} + \text{H}_2\text{O}\text{(l)} \rightleftharpoons \text{H}_3\text{O}^+\text{(aq)} + \text{In}^-\text{(aq)} \quad\quad K_a = 1.0 \times 10^{-5} \text{ at } 25\text{ }^\circ\text{C} \]

In this system, \(\text{HIn}\text{(aq)}\) is yellow and \(\text{In}^-\text{(aq)}\) is blue. A student adds a few drops of bromocresol green to a buffer solution with a \(\text{pH}\) of \(3.50\) at \(25\text{ }^\circ\text{C}\). Which of the following correctly identifies the predominant form of the indicator in the buffer solution and the observed color of the solution?

The acid-base indicator bromocresol green is a weak acid that dissociates in aqueous solution according to the equilibrium below.

\[ \text{HIn}\text{(aq)} + \text{H}_2\text{O}\text{(l)} \rightleftharpoons \text{H}_3\text{O}^+\text{(aq)} + \text{In}^-\text{(aq)} \quad\quad K_a = 1.0 \times 10^{-5} \text{ at } 25\text{ }^\circ\text{C} \]

In this system, \(\text{HIn}\text{(aq)}\) is yellow and \(\text{In}^-\text{(aq)}\) is blue. A student adds a few drops of bromocresol green to a buffer solution with a \(\text{pH}\) of \(3.50\) at \(25\text{ }^\circ\text{C}\). Which of the following correctly identifies the predominant form of the indicator in the buffer solution and the observed color of the solution?

- **A.** \(\text{HIn}\text{(aq)}\), and the solution appears yellow
- **B.** \(\text{HIn}\text{(aq)}\), and the solution appears blue
- **C.** \(\text{In}^-\text{(aq)}\), and the solution appears blue
- **D.** \(\text{In}^-\text{(aq)}\), and the solution appears yellow

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/123768/*