The number of water molecules is maximum in

Options

A. (a)18 grams of water
B. (b)18 moles of water
C. (c )18 molecules of water
D. (d)1.8 grams of water

Explanation

To determine which option has the maximum number of water molecules, we will calculate the number of water molecules for each option provided.

### Step-by-Step Solution:

1. **Calculate the number of water molecules in Option A (18 grams of water)**:
- The molecular weight of water (H2O) is calculated as follows:
- Hydrogen (H) = 1 g/mol (2 atoms) = 2 g/mol
- Oxygen (O) = 16 g/mol
- Total molecular weight of H2O = 2 + 16 = 18 g/mol
- Number of moles of water in 18 grams:
\[ \text{Number of moles} = \frac{\text{Weight}}{\text{Molecular Weight}} = \frac{18 \text{ g}}{18 \text{ g/mol}} = 1 \text{ mole} \]
- Number of water molecules:
\[ \text{Number of molecules} = 1 \text{ mole} \times 6.02 \times 10^{23} \text{ molecules/mole} = 6.02 \times 10^{23} \text{ molecules} \]

2. **Calculate the number of water molecules in Option B (18 moles of water)**:
- Number of water molecules:
\[ \text{Number of molecules} = 18 \text{ moles} \times 6.02 \times 10^{23} \text{ molecules/mole} = 18 \times 6.02 \times 10^{23} \text{ molecules} \]

3. **Calculate the number of water molecules in Option C (18 molecules of water)**:
- Number of water molecules is simply:
\[ 18 \text{ molecules} \]

4. **Calculate the number of water molecules in Option D (1.8 grams of water)**:
- Number of moles of water in 1.8 grams:
\[ \text{Number of moles} = \frac{1.8 \text{ g}}{18 \text{ g/mol}} = 0.1 \text{ moles} \]
- Number of water molecules:
\[ \text{Number of molecules} = 0.1 \text{ moles} \times 6.02 \times 10^{23} \text{ molecules/mole} = 0.1 \times 6.02 \times 10^{23} \text{ molecules} \]

5. **Compare the results**:
- Option A: \(6.02 \times 10^{23}\) molecules
- Option B: \(18 \times 6.02 \times 10^{23}\) molecules
- Option C: \(18\) molecules
- Option D: \(0.1 \times 6.02 \times 10^{23}\) molecules

The maximum number of water molecules is in **Option B**, which is \(18 \times 6.02 \times 10^{23}\) molecules.

### Final Answer:
**Option B has the maximum number of water molecules.**