The equation below shows the reaction of zinc with hydrochloric acid (HCl).

Zn (s) + 2 HCl (aq) - > ZnCl2 (aq) + H2 (g)

What will happen if the concentration of HCl is decreased?

A. More ZnCl2 will be produced.

B. The reaction rate will slow down.

C. The hydrochloric acid will become more acidic.

D. The reaction will produce water instead of hydrogen gas.

B. The reaction rate will slow down.

Explanation:

As concentration increases, rate of the reaction will increase. When there are more particles present in a system, more collision will take place.

As collision increases, rate of the reaction will increase. Concentration makes the molecules to come closer together thus leading to more collisions.

Rate of the reaction is directly proportional to the reactant collisions.

Orientation of the molecule and molecule possessing enough energy will lead to increased number of collisions thereby increasing the rate of the reaction.

So, Increasing the concentration of a reactant increases the frequency of collisions between reactants and will, therefore, increase the reaction rate

B.

Explanation:

If the concentration of acid is decreased the reaction rate will slow down as the hydrogen ion concentration will decrease.