To determine which of the statements regarding the production of hydrochloric acid (HCl) from sulfuric acid (H2SO4) are correct, we will analyze each statement step by step.
### Step-by-Step Solution:
1. **Understanding the Problem**:
We need to evaluate the correctness of four statements regarding the production of HCl from H2SO4. We know that sulfuric acid can produce hydrochloric acid in a specific ratio.
2. **Molecular Weights**:
- The molecular weight of H2SO4 (sulfuric acid) is 98 g/mol.
- The molecular weight of HCl (hydrochloric acid) is approximately 36.5 g/mol.
3. **Calculating the Amount of HCl**:
- For the first statement, we need to find out how much H2SO4 is required to produce 365 g of 40% HCl.
- The weight of HCl in the solution is 40% of 365 g:
\[
\text{Weight of HCl} = 0.40 \times 365 \, \text{g} = 146 \, \text{g}
\]
4. **Moles of HCl Produced**:
- To find the moles of HCl produced:
\[
\text{Moles of HCl} = \frac{146 \, \text{g}}{36.5 \, \text{g/mol}} = 4 \, \text{moles}
\]
5. **Relating H2SO4 to HCl**:
- From the stoichiometry, 1 mole of H2SO4 produces 2 moles of HCl.
- Therefore, to produce 4 moles of HCl, we need:
\[
\text{Moles of H2SO4} = \frac{4 \, \text{moles HCl}}{2} = 2 \, \text{moles H2SO4}
\]
6. **Mass of H2SO4 Required**:
- The mass of 2 moles of H2SO4 is:
\[
\text{Mass of H2SO4} = 2 \, \text{moles} \times 98 \, \text{g/mol} = 196 \, \text{g}
\]
- Thus, the first statement is correct.
7. **Evaluating the Second Statement**:
- The second statement claims that 245 g of 80% H2SO4 is needed.
- The weight of pure H2SO4 in 245 g of 80% solution is:
\[
\text{Weight of H2SO4} = 0.80 \times 245 \, \text{g} = 196 \, \text{g}
\]
- Since we already calculated that 196 g of H2SO4 is needed to produce 146 g of HCl, the second statement is also correct.
8. **Evaluating the Third Statement**:
- The third statement claims that 2 moles of pure H2SO4 are required for the production of 365 g of 40% HCl.
- As calculated, we need 2 moles of H2SO4 to produce 4 moles of HCl, confirming that the third statement is correct.
9. **Evaluating the Fourth Statement**:
- The fourth statement claims that 2.5 moles of 80% sulfuric acid are required for the production of 36.5 g of 40% HCl.
- First, calculate the weight of HCl:
\[
\text{Weight of HCl} = 0.40 \times 36.5 \, \text{g} = 14.6 \, \text{g}
\]
- The moles of HCl produced:
\[
\text{Moles of HCl} = \frac{14.6 \, \text{g}}{36.5 \, \text{g/mol}} \approx 0.4 \, \text{moles}
\]
- Moles of H2SO4 required:
\[
\text{Moles of H2SO4} = \frac{0.4 \, \text{moles HCl}}{2} = 0.2 \, \text{moles H2SO4}
\]
- The mass of 0.2 moles of pure H2SO4 is:
\[
\text{Mass of H2SO4} = 0.2 \times 98 \, \text{g/mol} = 19.6 \, \text{g}
\]
- The mass of 80% H2SO4 needed:
\[
\text{Mass of 80% H2SO4} = \frac{19.6 \, \text{g}}{0.80} = 24.5 \, \text{g}
\]
- Therefore, 2.5 moles of 80% H2SO4 is not required for 36.5 g of HCl, making the fourth statement incorrect.
### Conclusion:
- **Correct Statements**: 1, 2, and 3.
- **Incorrect Statement**: 4.
