`74.5 g` of a metallic chloride contain `35.5 g` of chlorine. The equivalent weight of the metal is

Options

A. 74.5
B. 39
C. 35.5
D. 7.45

Answer

To find the equivalent weight of the metal in the metallic chloride, we can follow these steps:

### Step 1: Calculate the Weight of the Metal
We know the total weight of the metallic chloride and the weight of chlorine in it. We can find the weight of the metal by subtracting the weight of chlorine from the total weight of the metallic chloride.

\[ \text{Weight of Metal} = \text{Weight of Metallic Chloride} - \text{Weight of Chlorine} \]

Substituting the values:

\[ \text{Weight of Metal} = 74.5 \, \text{g} - 35.5 \, \text{g} = 39 \, \text{g} \]

### Step 2: Understand the Concept of Equivalent Weight
The equivalent weight of a substance is defined as the mass of that substance that will combine with or displace 1 mole of hydrogen or 1 mole of electrons in a reaction. For chlorine, we know its equivalent weight is equal to its molar mass divided by its valency.

### Step 3: Determine the Equivalent Weight of Chlorine
Chlorine (Cl) has a molar mass of approximately 35.5 g/mol and a valency of 1. Therefore, the equivalent weight of chlorine is:

\[ \text{Equivalent Weight of Chlorine} = \frac{\text{Molar Mass of Chlorine}}{\text{Valency of Chlorine}} = \frac{35.5 \, \text{g/mol}}{1} = 35.5 \, \text{g} \]

### Step 4: Use the Formula for Equivalent Weights
We can use the relationship between the weights and equivalent weights of the metal and chlorine:

\[ \frac{\text{Weight of Metal}}{\text{Equivalent Weight of Metal}} = \frac{\text{Weight of Chlorine}}{\text{Equivalent Weight of Chlorine}} \]

Substituting the known values:

\[ \frac{39 \, \text{g}}{\text{Equivalent Weight of Metal}} = \frac{35.5 \, \text{g}}{35.5 \, \text{g}} \]

### Step 5: Solve for the Equivalent Weight of the Metal
Since the right side simplifies to 1, we can rearrange the equation:

\[ \text{Equivalent Weight of Metal} = 39 \, \text{g} \]

### Conclusion
Thus, the equivalent weight of the metal is **39 g**.