Select the correct statement.

Options

A. 2 moles of hydrochloric acid contain more hydrogen atoms than one mole of ammonia.
B. 0.1 mol of water contains the same number of molecules as 2.8 g of nitrogen gas.
C. The ratio of number of moles in 4.4 g of `CO_(2)` to 1.6 g of `SO_(2)`, is 1 : 4.
D. One mole of aluminium sulphate contains 4 moles of oxygen atoms.

Answer

To solve the question of selecting the correct statement, we will analyze each statement one by one.

### Step 1: Analyze the first statement
**Statement A:** "2 moles of HCl contain more hydrogen than 1 mole of ammonia."

- **Calculation for HCl:**
- HCl has 1 hydrogen atom per molecule.
- Therefore, 2 moles of HCl contain \(2 \times 1 = 2\) hydrogen atoms.

- **Calculation for NH3:**
- NH3 has 3 hydrogen atoms per molecule.
- Therefore, 1 mole of NH3 contains \(1 \times 3 = 3\) hydrogen atoms.

- **Conclusion:**
- 2 moles of HCl contain 2 hydrogen atoms, while 1 mole of NH3 contains 3 hydrogen atoms.
- Thus, this statement is **incorrect**.

### Step 2: Analyze the second statement
**Statement B:** "0.1 mole of water contains the same number of molecules as 2.8 grams of nitrogen gas."

- **Calculation for water:**
- 1 mole of water (H2O) contains Avogadro's number of molecules (\(N_A\)).
- Therefore, 0.1 mole of water contains \(0.1 \times N_A\) molecules.

- **Calculation for nitrogen gas:**
- Molar mass of nitrogen gas (N2) = 28 g/mol.
- Moles of nitrogen gas in 2.8 grams = \(\frac{2.8 \text{ g}}{28 \text{ g/mol}} = 0.1 \text{ moles}\).
- Therefore, 0.1 mole of nitrogen gas also contains \(0.1 \times N_A\) molecules.

- **Conclusion:**
- Both 0.1 mole of water and 2.8 grams of nitrogen gas contain the same number of molecules.
- Thus, this statement is **correct**.

### Step 3: Analyze the third statement
**Statement C:** "The ratio of number of moles in 4.4 grams of CO2 to 1.6 grams of SO2 is 1:4."

- **Calculation for CO2:**
- Molar mass of CO2 = 44 g/mol.
- Moles of CO2 in 4.4 grams = \(\frac{4.4 \text{ g}}{44 \text{ g/mol}} = 0.1 \text{ moles}\).

- **Calculation for SO2:**
- Molar mass of SO2 = 64 g/mol.
- Moles of SO2 in 1.6 grams = \(\frac{1.6 \text{ g}}{64 \text{ g/mol}} = 0.025 \text{ moles}\).

- **Ratio Calculation:**
- The ratio of moles of CO2 to SO2 = \(\frac{0.1}{0.025} = 4:1\).

- **Conclusion:**
- The statement claims the ratio is 1:4, which is incorrect. The correct ratio is 4:1.
- Thus, this statement is **incorrect**.

### Step 4: Analyze the fourth statement
**Statement D:** "1 mole of aluminum sulfate contains 4 moles of oxygen atoms."

- **Formula for aluminum sulfate:** \(Al_2(SO_4)_3\)
- **Atoms present:**
- Aluminum (Al): 2 atoms
- Sulfur (S): 3 atoms
- Oxygen (O): \(3 \times 4 = 12\) atoms

- **Moles of oxygen atoms:**
- 1 mole of aluminum sulfate contains 12 moles of oxygen atoms.

- **Conclusion:**
- The statement claims it contains 4 moles of oxygen atoms, which is incorrect.
- Thus, this statement is **incorrect**.

### Final Conclusion
The only correct statement is **Statement B**: "0.1 mole of water contains the same number of molecules as 2.8 grams of nitrogen gas."

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