Question

For a chemical reaction with rise in temperature by \(10^\circ C\) the rate constant is nearly:

• A. No change
• B. Tripled
• C. Doubled
• D. Ten time increases

Hint:

This is an approximate rule; actual increase depends on activation energy of the reaction.

Answer 1

The Correct Option is C

To solve this question, we need to consider the general rule for chemical reactions known as the "Temperature Coefficient Rule." It provides a rough estimation for the change in the rate constant of a reaction with a change in temperature. The rule states that for many reactions, the rate of reaction doubles for every increase in temperature by about \(10^\circ C\).

This rule is often attributed to the Arrhenius Equation, which is:

\(k = A e^{-\frac{E_a}{RT}}\)

Where:

• \(k\) is the rate constant.
• \(A\) is the pre-exponential factor.
• \(E_a\) is the activation energy.
• \(R\) is the universal gas constant.
• \(T\) is the temperature in Kelvin.

According to this, the rate constant is highly sensitive to changes in temperature because of the exponential relation. Typically, it's observed that a \(10^\circ C\) rise in temperature results in the doubling (or sometimes tripling) of the rate constant for many reactions.

Thus, for the given question, the reasoning leads to the conclusion that with an increase in temperature by \(10^\circ C\), the rate constant is likely to double.

Therefore, the correct answer is:

Doubled