Question

Why does the rate of the forward reaction increase when the surface area of a reactant is increased

?
When the surface area increases, the concentration of the substance increases, which reduces
the number of effective collisions.
When the surface area increases, the temperature of the system increases, which in turn
increases the number of effective collisions.
When the surface area increases, the density of the substance increases, which increases the
number of collisions.
When the surface area increases, the number of particle collisions increases, which in turn
increases the number of effective collisions.

Answer 1

Increasing the surface area of a reactant increases the frequency of collisions and increases the reaction rate. Several smaller particles have more surface area than one large particle. The more surface area that is available for particles to collide, the faster the reaction will occur.