Question detail

Why might predictions based on standard electrode potentials be inaccurate?

Try the question, check the answer, then read the explanation to understand the curriculum point.

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At a glance

MCQ

Type

practice

Style

Topic

Electrode potentials and electrochemical cells (A-level only)

Question

A. They do not consider the actual concentrations of reactants.
B. They assume all reactants are in excess.
C. They only apply to solid-state reactions.
D. They ignore the effect of catalysts.

Answer

They do not consider the actual concentrations of reactants.

Explanation

The correct option is They do not consider the actual concentrations of reactants.. They do not consider the actual concentrations of reactants. is the best answer because it directly supports the AQA A-Level Chemistry objective to explain limitations of predictions based on standard conditions. This reasoning is anchored to Feasibility and applications of cells (A-level only) in Electrode potentials and electrochemical cells (A-level only), and it separates predictions from similar A-Level ideas rather than relying on a vague recall statement. Other options are weaker if they use the wrong evidence, calculation, mechanism, observation, unit, or conclusion for this subtopic.

Common mistake

Misunderstanding Standard Conditions

Students often assume that predictions based on standard electrode potentials are always accurate in real-world conditions without considering limitations.

To correct this, remember that standard conditions (1 mol/dm³ concentration, 1 atm pressure, 25°C) may not reflect actual conditions in a cell. Always evaluate how changes in concentration or temperature can affect the electrode potential and the feasibility of the reaction. Keep the correction anchored to Feasibility and applications of cells (A-level only) and the objective: Explain limitations of predictions based on standard conditions.

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