Question

A gas is formed by the reaction between marble pieces and dilute $HCl$.
(a) Which gas is formed as a result of this reaction?
(b) Write the balanced chemical equation for this reaction.
(c) Suggest two ways of increasing the speed of the chemical reaction.

Answer 1

(a) Carbon dioxide gas
(b) $Ca{CO}_3+2HCl\to Ca{Cl}_2+{CO}_2+H_{2}O$
(c) Following are the ways of increasing the speed of the chemical reaction (Choose any 2):
(i) The speed of the reaction can be increased by cutting line stone into smaller pieces. When solid substances are split into small pieces, the surface area increases, resulting in an increase in the possibility of collision between reactant molecules. This is why the speed of the reaction increases.
(ii) The speed of the reaction can be increased the strength of the $HCl$ solution.
(iii) The speed of the reaction can also be increased by heating the contents (limestone in $HCl$). When heated, the kinetic energy of the molecules increases resulting in an increase in the number of effective collisions. This is why the speed of the reaction increases. In general, the speed of chemical reactions increases considerably on increasing the temperature.