In the reaction Zn + H2SO4Æ Zn SO4+ H2, which, if any, element is oxidized?
[A] Oxygen
[B] Zinc
[C] Hydrogen
[D] Sulfur
[E] None of these
The correct answer and explanation is :
The correct answer is [B] Zinc.
Explanation:
The reaction given is:
[ \text{Zn} + \text{H}_2\text{SO}_4 \rightarrow \text{ZnSO}_4 + \text{H}_2 ]
In this reaction, zinc (Zn) reacts with sulfuric acid (H₂SO₄) to form zinc sulfate (ZnSO₄) and hydrogen gas (H₂). To determine which element is oxidized, we need to understand the concepts of oxidation and reduction.
Oxidation is the process in which an element loses electrons, and reduction is when an element gains electrons. Let’s break down the changes in oxidation states of the elements involved.
- Zinc (Zn) starts as a pure metal (Zn), and it ends up in the form of zinc sulfate (ZnSO₄), where zinc has an oxidation state of +2. The oxidation state of zinc changes from 0 (in elemental zinc) to +2 (in ZnSO₄). Since zinc loses two electrons during this process, it is oxidized.
- Hydrogen (H) starts in sulfuric acid as H₂SO₄, where hydrogen has an oxidation state of +1. After the reaction, hydrogen ends up as H₂ gas, where the hydrogen atoms have an oxidation state of 0. Since hydrogen gains electrons in this process, it is reduced.
- Sulfur (S) in H₂SO₄ has an oxidation state of +6, and in ZnSO₄, it remains at +6, so sulfur is neither oxidized nor reduced.
- Oxygen (O) has an oxidation state of -2 in both H₂SO₄ and ZnSO₄, so oxygen is also neither oxidized nor reduced.
Thus, the element that undergoes oxidation (losing electrons) is zinc (Zn). Therefore, the correct answer is [B] Zinc.