When the same amount of zinc is treated separately with excess of sulphric acid and excess of sodium hydroxide, the ratio of volume of hydrogen evolved is

Options

A. `1:1`
B. `1:2`
C. `2:1`
D. `9:4`

Explanation

To determine the ratio of the volume of hydrogen evolved when the same amount of zinc is treated separately with excess sulfuric acid and excess sodium hydroxide, we can analyze the reactions involved.

### Step-by-Step Solution:

1. **Identify the Reactions:**
- When zinc (Zn) reacts with sulfuric acid (H₂SO₄), the reaction is:
\[ \text{Zn} + \text{H}_2\text{SO}_4 \rightarrow \text{ZnSO}_4 + \text{H}_2 \]
- When zinc reacts with sodium hydroxide (NaOH), the reaction is:
\[ \text{Zn} + 2\text{NaOH} \rightarrow \text{Na}_2\text{ZnO}_2 + \text{H}_2 \]

2. **Determine the Moles of Hydrogen Produced:**
- In the first reaction with sulfuric acid, one mole of zinc produces one mole of hydrogen gas (H₂).
- In the second reaction with sodium hydroxide, one mole of zinc also produces one mole of hydrogen gas (H₂).

3. **Volume of Hydrogen Gas:**
- According to Avogadro's law, equal volumes of gases at the same temperature and pressure contain equal numbers of molecules (or moles). Therefore, the volume of hydrogen gas produced is directly proportional to the number of moles of hydrogen gas.

4. **Calculate the Volume Ratio:**
- Since both reactions produce the same amount of hydrogen gas (1 mole of H₂ in each case), the volume of hydrogen gas evolved in both reactions will be the same.
- Thus, the ratio of the volume of hydrogen evolved when zinc is treated with sulfuric acid to the volume of hydrogen evolved when treated with sodium hydroxide is:
\[ \text{Ratio} = 1:1 \]

### Final Answer:
The ratio of the volume of hydrogen evolved is **1:1**.

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