For the reaction (hydrochloric acid + magnesium -> magnesium chloride + hydrogen) what would happen to the rate of reaction if the solid magnesium was cut into smaller pieces? Explain the change (4)

By cutting the solid magnesium into smaller pieces you are increasing the surface area and also making a larger surface area to volume ration. Increasing the surface area increases the rate of reaction as there is more available area for successful collisions to happen.