Question

Identify what would increase the reaction rate or decrease the reaction rate with the following changes to the chemical reaction conditions

Add an inhibitor

Increase surface area

Add a catalyst

Decrease temperature

Increase concentration

Agitating the solution

Answer 1

- Add an inhibitor — decrease the reaction rate.
Reason: inhibitors reduce the number of effective collisions or block active sites of catalysts, lowering the effective reaction pathway.

- Increase surface area — increase the reaction rate.
Reason: more exposed surface (for solid reactants) gives more area for collisions and reaction, increasing the frequency of reactive encounters.

- Add a catalyst — increase the reaction rate.
Reason: catalysts provide an alternative lower-activation-energy pathway (they are not consumed overall), so more collisions lead to product.

- Decrease temperature — decrease the reaction rate.
Reason: lower temperature reduces kinetic energy and the fraction of collisions with sufficient energy to overcome the activation barrier.

- Increase concentration — increase the reaction rate (except in some zero‑order cases).
Reason: higher concentration raises collision frequency between reactant molecules, so more reactions per unit time.

- Agitating the solution — generally increase the reaction rate.
Reason: stirring reduces diffusion limitations and boundary layers, improving mixing and collision frequency (especially important for heterogeneous or diffusion‑limited reactions).