The fizzing observed during the reactions is due to the release of hydrogen gas (H2). When magnesium (Mg) ribbon reacts with hydrochloric acid (HCl), it undergoes a single-displacement reaction, where Mg atoms replace hydrogen atoms in HCl, resulting in the formation of magnesium chloride (MgCl2) and hydrogen gas. The chemical equation for this reaction is:

Mg(s) + 2HCl(aq) → MgCl2(aq) + H2(g)

On the other hand, when magnesium ribbon reacts with acetic acid (CH3COOH), a weaker acid compared to HCl, it also undergoes a single-displacement reaction. However, the reaction proceeds at a slower rate due to the lower acidity of acetic acid. The chemical equation for this reaction is:

Mg(s) + 2CH3COOH(aq) → Mg(CH3COO)2(aq) + H2(g)

Comparing the two reactions, the reaction between Mg and HCl occurs more vigorously, resulting in more rapid fizzing. This difference can be attributed to the strength of the acids involved. Hydrochloric acid is a strong acid that completely dissociates in water, releasing a high concentration of hydrogen ions (H+). These H+ ions react quickly with Mg, leading to the rapid production of hydrogen gas and more vigorous fizzing.

In contrast, acetic acid is a weak acid that only partially dissociates in water, releasing a lower concentration of hydrogen ions. This results in a slower reaction with Mg and a less vigorous release of hydrogen gas, leading to less fizzing.