Question

Equal lengths of magnesium ribbons are taken in test tubes A and B. Hydrochloric acid is added to test tube A, while acetic acids are added to test tube B. The amount and concentration taken for both the acids are the same. In which test tube does the reaction occur more vigorously and why?

Answer 1

The reaction of acids with metal results in the evolution of hydrogen gas with the fizzing sound. The reaction rate of metal with acid depends on the strength of the acid.

Complete answer: In a test tube A, hydrochloric acid is taken and in a test tube B acetic acid is taken. Magnesium ribbon is added to both the test tubes and a fizzing sound is observed in both the test tubes due to the formation of hydrogen gas. Both the acids reacting with a metal releases hydrogen gas the only difference is which acid reacts faster with the metal.
The reaction of the acid with the metal depends on the strength of the acid. As hydrochloric acid is a strong acid it will give reaction with metal vigorously and evolve hydrogen gas with fizzing sound while acetic acid is a very weak acid, it will take time to react with the metal and slowly give hydrogen gas.
The reaction of Hydrochloric acid with metal is shown below.
$HCl(aq) + Mg(s) \to MgC{l_2}(aq) + {H_2}(g)$
In this reaction, hydrochloric acid reacts with magnesium ribbon to form magnesium chloride and hydrogen gas.
The reaction of acetic acid and magnesium ribbon is shown below.
$C{H_3}COOH(aq) + Mg(s) \to {(C{H_3}COO)_2}Mg + {H_2}(g)$
In this reaction, acetic acid reacts with magnesium ribbon to form magnesium acetate and hydrogen gas.

Note: The reaction of acids with metal is an example of exothermic reaction as hydrogen gas is released during the reaction by giving a fizzing sound due to the formation of bubbles.