Equivalent mass of a bivalent metal is 32.7g. Molecular mass of its chloride will be :

Options

A. 68.2
B. 103.7
C. 136.4
D. 166.3

Explanation

To find the molecular mass of the chloride of a bivalent metal with an equivalent mass of 32.7 g, we can follow these steps:

### Step 1: Understand the concept of equivalent mass
The equivalent mass of a substance is defined as the mass of that substance that combines with or displaces 1 mole of hydrogen or 8 grams of oxygen. For metals, the equivalent mass can be calculated using the formula:
\[ \text{Equivalent mass} = \frac{\text{Atomic mass}}{\text{Valency}} \]

### Step 2: Calculate the atomic mass of the bivalent metal
Since the metal is bivalent, its valency (n) is 2. We can rearrange the formula to find the atomic mass (M) of the metal:
\[ \text{Atomic mass} = \text{Equivalent mass} \times \text{Valency} \]
Substituting the values:
\[ \text{Atomic mass} = 32.7 \, \text{g} \times 2 = 65.4 \, \text{g} \]

### Step 3: Determine the formula of the chloride
For a bivalent metal (M), the chloride will have the formula \( \text{MCl}_2 \) because the metal has a +2 charge and chlorine has a -1 charge.

### Step 4: Calculate the molecular mass of the chloride
The molecular mass of \( \text{MCl}_2 \) can be calculated using the atomic masses:
\[ \text{Molecular mass} = \text{Atomic mass of M} + 2 \times \text{Atomic mass of Cl} \]
The atomic mass of chlorine (Cl) is approximately 35.5 g. Therefore:
\[ \text{Molecular mass} = 65.4 \, \text{g} + 2 \times 35.5 \, \text{g} \]
\[ \text{Molecular mass} = 65.4 \, \text{g} + 71.0 \, \text{g} = 136.4 \, \text{g/mol} \]

### Final Answer
The molecular mass of the chloride is **136.4 g/mol**.

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