Which of the following will only affect the reaction rate of gases? A. Concentration
B. Catalyst
C. Pressure
D. Surface area

D. Pressure

Explanation:

The rate of a reaction is defined as the speed at which the reactants are converted into products. Factors influencing the rate of a reaction are concentration, catalyst, temperature, surface area,  and pressure, etc.

In case of the reaction rate of gases, pressure will only have its affect as pressure do not have any influence on solid and liquid.

While concentration, surface area and catalyst influence all reaction rates including solid, liquids and gases.

Hence, the correct option is (d) pressure.

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