The molality of the solution containing 45g of glucose dissolved in 2kg of water is ?

Options

A. 0.125m
B. 0.225m
C. 0.425m
D. 0.356m

Explanation

To find the molality of a solution containing 45g of glucose dissolved in 2kg of water, we can follow these steps:

### Step 1: Calculate the number of moles of glucose.
To find the number of moles, we use the formula:

\[ \text{Number of moles} = \frac{\text{mass of solute (g)}}{\text{molar mass of solute (g/mol)}} \]

Given:
- Mass of glucose (solute) = 45g
- Molar mass of glucose = 180 g/mol

Substituting the values:

\[ \text{Number of moles of glucose} = \frac{45 \text{ g}}{180 \text{ g/mol}} = 0.25 \text{ moles} \]

### Step 2: Identify the mass of the solvent in kg.
The mass of the solvent (water) is given as 2 kg.

### Step 3: Calculate the molality of the solution.
Molality (m) is defined as the number of moles of solute per kilogram of solvent:

\[ \text{Molality (m)} = \frac{\text{Number of moles of solute}}{\text{Mass of solvent (kg)}} \]

Substituting the values:

\[ \text{Molality} = \frac{0.25 \text{ moles}}{2 \text{ kg}} = 0.125 \text{ mol/kg} \]

### Final Answer:
The molality of the solution is **0.125 mol/kg**.

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