Question

To make sure he learnt the constant of rate constant properly, Samwell Tarly tried an experiment. He tried to vary the conditions of the reaction and see how it affected the rate constant.

He performed the following reactions
$2H_2+O_2\to 2H_{2}O$

• A. He changed the temperature of the reaction
• B. He changed the concentrations of the reactants
• C. He replaced $O_{2}with{F}_2$
• D. He used a catalyst in the reaction

Answer 1

The correct option is C He replaced $O_{2}with{F}_2$

Let us break this down one by one.

Remember the definition of rate constant? We said that the concentration of the reactants is taken as one. This means that the rate constant is independent of the concentration of the reactants. It is a constant for a given reaction at a given temperature.

By changing the temperature of the reaction, we already know that the rate of the reaction is affected. So, logically the rate constant would also be affected.

Changing the reactants themselves would definitely affect the rate of the reaction, since the reaction itself is different!

And we all know that a catalyst usually increases the rate of the reaction but it is also possible to have negative catalysts/inhibitors which would reduce the rate of the reaction. In either case, the rate constant is affected.