Which of thes reactions will not produce hydrogen gas as a by-product?

Options

A. Reaction of sodium with water
B. Reaction of zinc with sodium hydroxide
C. Reaction of iron with dilute hydrochloric acid
D. Reaction of zinc with oxygen

Answer

To determine which reaction will not produce hydrogen gas as a by-product, we will analyze each given reaction step by step.

### Step 1: Analyze the reaction of Sodium with Water
- **Reaction**: Sodium (Na) + Water (H2O) → Sodium Hydroxide (NaOH) + Hydrogen Gas (H2)
- **Balanced Equation**: 2Na + 2H2O → 2NaOH + H2
- **Conclusion**: This reaction produces hydrogen gas as a by-product.

### Step 2: Analyze the reaction of Zinc with Sodium Hydroxide
- **Reaction**: Zinc (Zn) + Sodium Hydroxide (NaOH) → Sodium Zincate + Hydrogen Gas (H2)
- **Balanced Equation**: Zn + 2NaOH → Na2ZnO2 + H2
- **Conclusion**: This reaction also produces hydrogen gas as a by-product.

### Step 3: Analyze the reaction of Iron with Dilute Hydrochloric Acid
- **Reaction**: Iron (Fe) + Dilute Hydrochloric Acid (HCl) → Iron(II) Chloride (FeCl2) + Hydrogen Gas (H2)
- **Balanced Equation**: Fe + 2HCl → FeCl2 + H2
- **Conclusion**: This reaction produces hydrogen gas as a by-product as well.

### Step 4: Analyze the reaction of Zinc with Oxygen
- **Reaction**: Zinc (Zn) + Oxygen (O2) → Zinc Oxide (ZnO)
- **Balanced Equation**: 2Zn + O2 → 2ZnO
- **Conclusion**: This reaction does not produce hydrogen gas as a by-product.

### Final Answer
Based on the analysis, the reaction that will not produce hydrogen gas as a by-product is:
**Option D: Zinc with Oxygen.**

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