For a first order reaction, which of the following statements is INCORRECT?

On introducing catalyst, both rate constant and rate of reaction increases.
On increasing temperature both rate constant & rate of reaction increases.
On decreasing volume both rate constant & rate of gaseous reaction increases.
On increasing concentration of gaseous reactant at constant volume & constant temperature both total pressure and rate of the reaction increases.

Correct answer: On decreasing volume both rate constant & rate of gaseous reaction increases.

Solution

Reducing volume increases concentration so the rate rises, but the rate constant k depends only on temperature (and catalyst), so it does NOT change; hence that statement is incorrect.

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