Question

Difficulty: EasySalt Hydrolysis and Solution Acidity/Alkalinity

An aqueous solution of sodium chloride (NaClNaCl) undergoes salt hydrolysis, causing it to turn blue litmus paper red.

Answer: Answer

Answer

The statement is false. Sodium chloride (NaClNaCl) is a neutral salt of a strong acid (HClHCl) and a strong base (NaOHNaOH); its ions do not undergo hydrolysis in aqueous solution.
The statement is false because sodium chloride (NaClNaCl) originates from a strong acid (HClHCl) and a strong base (NaOHNaOH). Since neither cation (Na+Na^+) nor anion (ClCl^-) reacts hydrolytically with water, the aqueous solution maintains a neutral pH\text{pH} of 7 and has no effect on blue litmus paper.

Step-by-Step Solution

1
Identify the parent acid and base that form sodium chloride (NaClNaCl).
The parent acid is hydrochloric acid (HClHCl, a strong acid) and the parent base is sodium hydroxide (NaOHNaOH, a strong base).
Knowing the relative strengths of the parent acid and base determines whether hydrolysis occurs.
2
Determine the hydrolysis tendency of the constituent ions (Na+Na^+ and ClCl^-).
Neither Na+Na^+ nor ClCl^- undergoes hydrolysis in aqueous solution.
Conjugate ions of strong acids and strong bases are extremely weak and do not react with water molecules.
3
Deduce the solution acidity/alkalinity and its effect on litmus paper.
The concentrations of H+H^+ and OHOH^- remain equal, giving a neutral solution (pH=7\text{pH} = 7) that does not turn blue litmus paper red.
Without hydrolysis generating excess H+H^+ ions, the solution cannot display acidic behavior.

Key Concept

Salts derived from strong acids and strong bases yield neutral aqueous solutions because their ions do not hydrolyze.
Estimated Time:45s
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