Effect of size in marble chips reacts with hydrochloric acid?

Your question is: how does the size of marble chips affect their rate of reaction with hydrochloric acid. The answer is: The larger the marble chips, the less surface area there is. The less surface area there is the lower the rate of reaction. You can explain this using collision theory: by having a smaller surface area few 'formula unit' (in this case) or molecules are available to collide with the other reactant (HCl). Therefore there are less frequent collisions between the reactants and the reaction procedes slower.