The mass of NaCl required to prepare 0.06 m aqueous solution in 1kg water is

Options

A. 2.51g
B. 3.51g
C. 5.5g
D. 1.3g

Explanation

To find the mass of NaCl required to prepare a 0.06 molal (m) aqueous solution in 1 kg of water, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Definition of Molality**:
Molality (m) is defined as the number of moles of solute per kilogram of solvent. The formula for molality is:
\[ m = \frac{\text{Number of moles of solute}}{\text{Mass of solvent in kg}} \]

2. **Identify Given Values**:
- Molality (m) = 0.06 m
- Mass of solvent (water) = 1 kg

3. **Calculate the Number of Moles of NaCl**:
Rearranging the molality formula to find the number of moles of solute:
\[ \text{Number of moles of NaCl} = m \times \text{Mass of solvent in kg} \]
Substituting the values:
\[ \text{Number of moles of NaCl} = 0.06 \, \text{mol/kg} \times 1 \, \text{kg} = 0.06 \, \text{moles} \]

4. **Calculate the Mass of NaCl**:
The mass of NaCl can be calculated using the formula:
\[ \text{Mass of NaCl} = \text{Number of moles} \times \text{Molar mass of NaCl} \]
The molar mass of NaCl is 58.5 g/mol. Therefore:
\[ \text{Mass of NaCl} = 0.06 \, \text{moles} \times 58.5 \, \text{g/mol} \]
\[ \text{Mass of NaCl} = 3.51 \, \text{grams} \]

5. **Final Result**:
The mass of NaCl required to prepare a 0.06 m aqueous solution in 1 kg of water is **3.51 grams**.