the number of electrons required to deposit 1g equivalent aluminium (At. Wt. =27) from a solution of aluminium chloride will be

Options

A. 1
B. 2
C. 3
D. 4

Explanation

To determine the number of electrons required to deposit 1 gram equivalent of aluminium from a solution of aluminium chloride, we can follow these steps:

### Step 1: Understand the concept of gram equivalent
The gram equivalent of an element is the mass of the element that combines with or displaces 1 mole of hydrogen (or 1 mole of electrons). For aluminium (Al), the atomic weight is 27 g/mol.

### Step 2: Calculate the gram equivalent of aluminium
The gram equivalent can be calculated using the formula:
\[ \text{Gram Equivalent} = \frac{\text{Atomic Weight}}{\text{Valency}} \]
For aluminium, the valency is 3 (since aluminium typically forms Al³⁺ ions). Therefore:
\[ \text{Gram Equivalent} = \frac{27 \text{ g}}{3} = 9 \text{ g} \]
This means that 9 grams of aluminium corresponds to 1 gram equivalent of aluminium.

### Step 3: Determine the number of electrons required for 1 gram equivalent
Since 27 grams of aluminium requires 3 electrons to be deposited (as per the reaction: Al³⁺ + 3e⁻ → Al), we need to find out how many electrons are required for 9 grams of aluminium.

Using the unitary method:
- 27 grams of aluminium requires 3 electrons.
- Therefore, 9 grams of aluminium will require:
\[ \text{Electrons for 9 g} = \frac{3 \text{ electrons}}{27 \text{ g}} \times 9 \text{ g} = 1 \text{ electron} \]

### Conclusion
Thus, the number of electrons required to deposit 1 gram equivalent of aluminium from a solution of aluminium chloride is **1 electron**.

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