To dissolve 0.9 g metal, 100 mL of 1 N HCl is used. What is the equivalent weight of metal?

Options

A. 7
B. 9
C. 10
D. 6

Answer

To find the equivalent weight of the metal, we can use the formula for normality (N):

\[ N = \frac{\text{Weight of solute (g)}}{\text{Equivalent weight (g/equiv)} \times \text{Volume of solution (L)}} \]

### Step 1: Identify the given values
- Weight of the metal = 0.9 g
- Normality (N) of HCl = 1 N
- Volume of HCl solution = 100 mL = 0.1 L (since 1000 mL = 1 L)

### Step 2: Substitute the known values into the normality formula
We can rearrange the normality formula to solve for the equivalent weight:

\[ \text{Equivalent weight} = \frac{\text{Weight of solute (g)}}{N \times \text{Volume of solution (L)}} \]

Substituting the known values:

\[ \text{Equivalent weight} = \frac{0.9 \, \text{g}}{1 \, \text{N} \times 0.1 \, \text{L}} \]

### Step 3: Calculate the equivalent weight
Now, calculate the equivalent weight:

\[ \text{Equivalent weight} = \frac{0.9 \, \text{g}}{0.1} = 9 \, \text{g/equiv} \]

### Conclusion
The equivalent weight of the metal is **9 g/equiv**.

---