---
title: "A student mixes aqueous solutions of \\(\\text{Ba(NO}_3)_2\\) and \\(\\text{Na}_2\\text{SO}_4\\), observing the immediate formation of a white precipitate of \\(\\text{BaSO}_4\\text{(s)}\\). The net ionic equation for the precipitation process is shown below.  \\[\\text{Ba}^{2+}\\text{(aq)} + \\text{SO}_4^{2-}\\text{(aq)} \\rightarrow \\text{BaSO}_4\\text{(s)}\\]  Which of the following best predicts and explains the sign of \\(\\Delta S^\\circ\\) for this reaction?"
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url: "https://nerd-notes.com/ubq/121388/"
date_modified: "2026-08-23T05:02:01+00:00"
---

# A student mixes aqueous solutions of \(\text{Ba(NO}_3)_2\) and \(\text{Na}_2\text{SO}_4\), observing the immediate formation of a white precipitate of \(\text{BaSO}_4\text{(s)}\). The net ionic equation for the precipitation process is shown below.

\[\text{Ba}^{2+}\text{(aq)} + \text{SO}_4^{2-}\text{(aq)} \rightarrow \text{BaSO}_4\text{(s)}\]

Which of the following best predicts and explains the sign of \(\Delta S^\circ\) for this reaction?

A student mixes aqueous solutions of \(\text{Ba(NO}_3)_2\) and \(\text{Na}_2\text{SO}_4\), observing the immediate formation of a white precipitate of \(\text{BaSO}_4\text{(s)}\). The net ionic equation for the precipitation process is shown below.

\[\text{Ba}^{2+}\text{(aq)} + \text{SO}_4^{2-}\text{(aq)} \rightarrow \text{BaSO}_4\text{(s)}\]

Which of the following best predicts and explains the sign of \(\Delta S^\circ\) for this reaction?

- **A.** \(\Delta S^\circ > 0\), because the formation of a solid precipitate increases the stability and disorder of the system.
- **B.** \(\Delta S^\circ > 0\), because energy is released when ionic bonds form in the solid crystal lattice.
- **C.** \(\Delta S^\circ < 0\), because mobile aqueous ions become fixed into a rigid, ordered crystal lattice, decreasing the dispersal of matter.
- **D.** \(\Delta S^\circ < 0\), because the total number of atoms in the system decreases as the precipitate forms.

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121388/*