Question

Suggest a reason for each observation given below.
i) In fireworks, powdered magnesium is used rather than magnesium ribbon.
ii) Zinc and dilute $H_{2}S{O}_4$ react much more quickly when a few drops of copper sulphate solution are added.
iii) The reaction between magnesium carbonate and dilute hydrochloric acid speeds up when some concentrated $HCl$ is added.

Answer 1

(i) Powdered $Mg$ have more surface area, as compared with $Mg$ ribbon. Therefore, for fast reaction powdered $Mg$ is used.

(ii) When few drops of $CuS{O}_4$ is added to the $Zn$ and diluted $H_{2}S{O}_4$ reaction, reaction proceeds further at faster rate because $CuS{O}_4$ acts as a catalyst for a reaction.

(iii) The reaction speeds up when some concentrated $HCl$ is added because concentrated $HCl$ is more strong in acidic character, which replaces the $Mg(C{O}_3{)}_2$ more effectively and thus, reaction proceeds at a much faster rate.