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Difficulty: HardPhysical and Chemical Properties of Acids and Bases

A concentrated solution of ethanoic acid (CH3COOHCH_3COOH) exhibits higher electrical conductivity than a dilute solution of hydrochloric acid (HClHCl) because the higher concentration provides a greater total number of free mobile ions.

Answer: Answer

Answer

The statement is False. Dilute hydrochloric acid conducts electricity more effectively than concentrated ethanoic acid because hydrochloric acid is a strong acid that ionizes completely to yield a higher concentration of free mobile ions.
The statement is false because the electrical conductivity of an electrolyte solution depends strictly on the concentration of free mobile ions available to carry electric current. Hydrochloric acid (HClHCl) is a strong acid that ionizes completely in water, yielding a high density of H+H^+ and Cl−Cl^- ions. Ethanoic acid (CH3COOHCH_3COOH) is a weak acid that ionizes only slightly in water, leaving most molecules unionized. Consequently, even a dilute solution of HClHCl has a much higher concentration of mobile ions and a higher electrical conductivity than a concentrated solution of ethanoic acid.

Step-by-Step Solution

1
Analyze the acid strength and degree of ionization of both compounds.
Hydrochloric acid (HClHCl) is a strong acid that undergoes complete ionization (HCl(aq)→H+(aq)+Cl−(aq)HCl(aq) \rightarrow H^+(aq) + Cl^-(aq)), whereas ethanoic acid (CH3COOHCH_3COOH) is a weak acid that undergoes partial ionization (CH3COOH(aq)⇌H+(aq)+CH3COO−(aq)CH_3COOH(aq) \rightleftharpoons H^+(aq) + CH_3COO^-(aq)).
Electrical conductivity in aqueous solutions depends directly on the concentration of free, mobile charge-carrying ions.
2
Compare the concentration of mobile ions in concentrated weak acid vs. dilute strong acid.
Despite having a high molecular concentration, concentrated ethanoic acid contains mostly neutral, unionized molecules and very few free ions. Dilute HClHCl, even at lower molarity, yields a significantly higher concentration of free ions due to complete dissociation.
Only ionized species conduct electricity in solution; neutral molecules do not carry current.
3
Determine the relative electrical conductivity and evaluate the statement.
Dilute HClHCl is a far better conductor of electricity than concentrated CH3COOHCH_3COOH. Thus, the claim in the statement is false.
High acid concentration does not guarantee high conductivity if the acid is weak.

Key Concept

Electrical Conductivity and Ionization of Strong vs. Weak Acids
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Topics

Physical and Chemical Properties of Acids and Bases

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