The molality of the solution containing 45g of glucose dissolved in 1kg of water is ?

Options

A. 0.25
B. 2.5
C. 0.12
D. 0.36

Explanation

To find the molality of the solution containing 45g of glucose dissolved in 1kg of water, we can follow these steps:

### Step 1: Calculate the number of moles of glucose
To calculate the number of moles of glucose, 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 = 45 g
- Molar mass of glucose (C₆H₁₂O₆) = 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
The mass of the solvent (water) is given as:

\[ \text{Mass of solvent} = 1 \, \text{kg} \]

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

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

Substituting the values we found:

\[ \text{Molality} = \frac{0.25 \, \text{moles}}{1 \, \text{kg}} = 0.25 \, \text{mol/kg} \]

### Final Answer:
The molality of the solution is **0.25 mol/kg**.

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