Which is a sources of nascent hydrogen?
(i) Zn + dil HCl
ii `CH_(3)OH + Na`
(iii) Electrolysis of `H_(2)O`
(iv) Silent electric discharge of `H_(2)O_(2)`

Options

A. I & II
B. II & III
C. I, II, III
D. IV

Answer

To determine which of the given options is a source of nascent hydrogen, we will analyze each option step by step.

### Step 1: Understand Nascent Hydrogen
Nascent hydrogen refers to hydrogen in its atomic form, which is often represented as [H]. It is considered "newly born" hydrogen that is formed during certain chemical reactions.

### Step 2: Analyze Each Option
1. **Zn + Dilute HCl**:
- When zinc (Zn) reacts with dilute hydrochloric acid (HCl), it produces zinc chloride (ZnCl2) and hydrogen gas (H2).
- The reaction can be represented as:
\[ Zn + 2HCl \rightarrow ZnCl_2 + H_2 \]
- During this reaction, nascent hydrogen is produced as the hydrogen atoms are released in a reactive form.
- **Conclusion**: This option produces nascent hydrogen.

2. **CH3OH + Na**:
- When methanol (CH3OH) reacts with sodium (Na), sodium replaces the acidic hydrogen in methanol, forming sodium methoxide (CH3ONa) and nascent hydrogen.
- The reaction can be represented as:
\[ 2CH_3OH + 2Na \rightarrow 2CH_3ONa + H_2 \]
- Here, nascent hydrogen is also produced.
- **Conclusion**: This option produces nascent hydrogen.

3. **Electrolysis of H2O**:
- Electrolysis of water involves passing an electric current through water to decompose it into hydrogen and oxygen gases.
- The reactions at the electrodes are:
- At cathode: \(2H_2O + 2e^- \rightarrow H_2 + 2OH^-\)
- At anode: \(2H_2O \rightarrow O_2 + 4H^+ + 4e^-\)
- While hydrogen gas is produced, there is no formation of nascent hydrogen.
- **Conclusion**: This option does not produce nascent hydrogen.

4. **Silent Electric Discharge of H2O2**:
- Silent electric discharge of hydrogen peroxide (H2O2) leads to the decomposition of H2O2 into water and oxygen, and it can also produce hydrogen gas.
- The reaction can be represented as:
\[ 2H_2O_2 \rightarrow 2H_2O + O_2 \]
- However, nascent hydrogen is not formed in this process.
- **Conclusion**: This option does not produce nascent hydrogen.

### Final Conclusion
From the analysis:
- **Option 1 (Zn + Dil HCl)**: Produces nascent hydrogen.
- **Option 2 (CH3OH + Na)**: Produces nascent hydrogen.
- **Option 3 (Electrolysis of H2O)**: Does not produce nascent hydrogen.
- **Option 4 (Silent Electric Discharge of H2O2)**: Does not produce nascent hydrogen.

Thus, the correct sources of nascent hydrogen are **(i) Zn + Dil HCl** and **(ii) CH3OH + Na**.

### Answer
The sources of nascent hydrogen are (i) Zn + dil HCl and (ii) CH3OH + Na.

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