By carrying electrolysis of which compound , pure hydrogen is obtained

Options

A. Water containing `H_2SO_4`
B. Water containing NaOH
C. `Ba(OH)_2` solution
D. KOH solution

Answer

To determine which compound, when subjected to electrolysis, yields pure hydrogen, we can analyze the process of electrolysis itself. Here’s a step-by-step solution:

### Step 1: Understand Electrolysis
Electrolysis is a chemical process that uses electrical energy to drive a non-spontaneous reaction. It involves the breakdown of a compound into its constituent elements or ions.

**Hint:** Remember that electrolysis requires an electrolyte, which can be a liquid or solution that conducts electricity.

### Step 2: Identify Suitable Compounds
Common compounds that can be electrolyzed to produce hydrogen include water (H2O), sodium chloride (NaCl), and barium hydroxide (Ba(OH)2). However, the purity of hydrogen produced can vary based on the compound used.

**Hint:** Consider the compounds that can dissociate into ions and produce hydrogen gas at the cathode during electrolysis.

### Step 3: Electrolysis of Barium Hydroxide
When barium hydroxide (Ba(OH)2) is electrolyzed, it dissociates into barium ions (Ba²⁺) and hydroxide ions (OH⁻). At the cathode, reduction occurs where hydroxide ions gain electrons to form hydrogen gas (H2).

The reaction can be summarized as:
\[ 2 \text{H}_2\text{O} + 2 \text{e}^- \rightarrow \text{H}_2 + 2 \text{OH}^- \]

**Hint:** Focus on the cathodic reaction where hydrogen is produced and consider the role of hydroxide ions.

### Step 4: Anodic Reaction
At the anode, the hydroxide ions can lose electrons to form oxygen gas (O2):
\[ 4 \text{OH}^- \rightarrow 2 \text{H}_2\text{O} + \text{O}_2 + 4 \text{e}^- \]

**Hint:** Remember that the anode reaction involves the oxidation of hydroxide ions, which is crucial for balancing the overall reaction.

### Step 5: Purity of Hydrogen
While barium hydroxide does produce hydrogen gas, there may be some oxygen present due to the reactions occurring at the anode. However, the hydrogen gas can be purified after collection.

**Hint:** Consider the implications of any by-products formed during the electrolysis process.

### Conclusion
The compound that yields pure hydrogen upon electrolysis is **barium hydroxide (Ba(OH)2)**.

**Final Answer:** Barium hydroxide (Ba(OH)2)