---
title: "A student mixes \\(100.0 \\text{ mL}\\) of \\(0.200 \\text{ M } \\text{Pb(NO}_3)_2\\text{(aq)}\\) with \\(100.0 \\text{ mL}\\) of \\(0.300 \\text{ M } \\text{KI(aq)}\\), resulting in the formation of a yellow precipitate according to the balanced net ionic equation below.  \\[\\text{Pb}^{2+}\\text{(aq)} + 2\\,\\text{I}^-\\text{(aq)} \\rightarrow \\text{PbI}_2\\text{(s)}\\]  Assuming the reaction goes to completion, how many moles of the excess reactant remain unreacted?"
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url: "https://nerd-notes.com/ubq/119237/"
date_modified: "2026-08-19T12:39:30+00:00"
---

# A student mixes \(100.0 \text{ mL}\) of \(0.200 \text{ M } \text{Pb(NO}_3)_2\text{(aq)}\) with \(100.0 \text{ mL}\) of \(0.300 \text{ M } \text{KI(aq)}\), resulting in the formation of a yellow precipitate according to the balanced net ionic equation below.

\[\text{Pb}^{2+}\text{(aq)} + 2\,\text{I}^-\text{(aq)} \rightarrow \text{PbI}_2\text{(s)}\]

Assuming the reaction goes to completion, how many moles of the excess reactant remain unreacted?

A student mixes \(100.0 \text{ mL}\) of \(0.200 \text{ M } \text{Pb(NO}_3)_2\text{(aq)}\) with \(100.0 \text{ mL}\) of \(0.300 \text{ M } \text{KI(aq)}\), resulting in the formation of a yellow precipitate according to the balanced net ionic equation below.

\[\text{Pb}^{2+}\text{(aq)} + 2\,\text{I}^-\text{(aq)} \rightarrow \text{PbI}_2\text{(s)}\]

Assuming the reaction goes to completion, how many moles of the excess reactant remain unreacted?

- **A.** \(0.0050 \text{ mol}\)
- **B.** \(0.0100 \text{ mol}\)
- **C.** \(0.0150 \text{ mol}\)
- **D.** \(0.0200 \text{ mol}\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/119237/*