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When sodium chloride (NaCl) dissolves in water, which of the following statements are true?
publish date: 2025/11/10 04:06:00 UTC
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\[ \mathrm{NaCl{(s)} \xrightarrow[\text{}]{H_2O} Na^+{(aq)} + Cl^-{(aq)}} \]
Correct Answer
(1) The Na⁺ and Cl⁻ ions separate and move independently in solution
(2) The process is called dissociation
(3) The (aq) label indicates the ions are dissolved in water
Explanation
When NaCl dissolves in water, the ions separate and go their own way in solution; the ions are now written with their respective charges, and the (aq) phase label emphasizes that they are dissolved. This process is called dissociation; we say that the ions dissociate.
Back in 1884, a young Swedish chemist named Svante August Arrhenius proposed in his PhD dissertation that ionic compounds, like NaCl, dissolve in water by separating into individual ions—each going its own way in solution. He even suggested that all ionic compounds that dissolve behave this way. But his examiners didn’t believe him. They thought his idea was far-fetched and gave him only a barely passing grade. Years later, that same groundbreaking work became a foundation of modern chemistry—and in 1903, Arrhenius was awarded the Nobel Prize in Chemistry for his contributions to understanding electrolytic dissociation.
Reference
Beginning Chemistry v. 1.0, go-math-science.com