During electrolysis of fused aluminium chloride 0.9gm of aluminium was deposited on the cathode. Thevolume of chlorine liberated at the anode will be

Options

A. 2.24 litres
B. 11.2 litres
C. 1.12 litres
D. 5.6 litres

Answer

To solve the problem of determining the volume of chlorine gas liberated at the anode during the electrolysis of fused aluminium chloride, we will follow these steps:

### Step 1: Calculate the equivalent weight of Aluminium (Al)
The equivalent weight of Aluminium (Al) can be calculated using the formula:
\[ \text{Equivalent Weight} = \frac{\text{Molar Mass}}{n} \]
where \( n \) is the number of electrons exchanged per atom during the reaction. For Aluminium, \( n = 3 \) (as it forms Al³⁺ ions). The molar mass of Aluminium is approximately 27 g/mol.

\[ \text{Equivalent Weight of Al} = \frac{27 \, \text{g/mol}}{3} = 9 \, \text{g/equiv} \]

### Step 2: Calculate the equivalent weight of Chlorine (Cl)
The equivalent weight of Chlorine (Cl) is calculated similarly. Chlorine gas (Cl₂) has a molar mass of approximately 71 g/mol (35.5 g/mol per Cl atom). Since Cl₂ gains 2 electrons to form 2 Cl⁻ ions, \( n = 2 \).

\[ \text{Equivalent Weight of Cl} = \frac{71 \, \text{g/mol}}{2} = 35.5 \, \text{g/equiv} \]

### Step 3: Calculate the gram equivalent of Aluminium deposited
The mass of Aluminium deposited on the cathode is given as 0.9 g. The gram equivalent of Aluminium can be calculated as follows:

\[ \text{Gram Equivalent of Al} = \frac{\text{Mass of Al}}{\text{Equivalent Weight of Al}} = \frac{0.9 \, \text{g}}{9 \, \text{g/equiv}} = 0.1 \, \text{equiv} \]

### Step 4: Calculate the gram equivalent of Chlorine liberated
According to the stoichiometry of the electrolysis process, the gram equivalent of Chlorine liberated will be equal to the gram equivalent of Aluminium deposited.

\[ \text{Gram Equivalent of Cl} = 0.1 \, \text{equiv} \]

### Step 5: Calculate the mass of Chlorine liberated
Using the equivalent weight of Chlorine, we can find the mass of Chlorine liberated:

\[ \text{Mass of Cl} = \text{Gram Equivalent of Cl} \times \text{Equivalent Weight of Cl} = 0.1 \, \text{equiv} \times 35.5 \, \text{g/equiv} = 3.55 \, \text{g} \]

### Step 6: Calculate the volume of Chlorine gas liberated
To find the volume of Chlorine gas at standard temperature and pressure (STP), we use the molar volume of a gas, which is 22.4 L/mol. First, we need to calculate the number of moles of Chlorine liberated:

\[ \text{Moles of Cl} = \frac{\text{Mass of Cl}}{\text{Molar Mass of Cl2}} = \frac{3.55 \, \text{g}}{71 \, \text{g/mol}} \approx 0.05 \, \text{mol} \]

Now, we can calculate the volume of Chlorine gas:

\[ \text{Volume of Cl2} = \text{Moles of Cl2} \times 22.4 \, \text{L/mol} = 0.05 \, \text{mol} \times 22.4 \, \text{L/mol} \approx 1.12 \, \text{L} \]

### Final Answer
The volume of chlorine liberated at the anode will be approximately **1.12 L**.

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