Which compound will absorb the maximum amount of heat when dissolved in the same amount of water ? (Integral heats of solution at` 25^(@)C` in kcal/mol of each solute are given in brackets)

Options

A. `HCI (Delta H = -17.74)`
B. `HNO_(3)(Delta H = -7.85)`
C. `NH_(4) NO_(3) (Delta H = + 16.8)`
D. `NaCI (Delta H = +1.02)`

Answer

To determine which compound will absorb the maximum amount of heat when dissolved in the same amount of water, we need to analyze the given integral heats of solution (ΔH) for each solute at 25°C. The key point to remember is that a higher positive value of ΔH indicates that more heat is absorbed during the dissolution process.

### Step-by-Step Solution:

1. **Understand the Concept of Heat of Solution (ΔH)**:
- The heat of solution (ΔH) is the amount of heat absorbed or released when a solute dissolves in a solvent (water in this case). A positive ΔH indicates that the process is endothermic, meaning heat is absorbed from the surroundings.

2. **Identify the Given Values**:
- We need to look at the integral heats of solution provided for each compound. For example, if the values are:
- Compound A: ΔH = +1.08 kcal/mol
- Compound B: ΔH = +16.8 kcal/mol
- Compound C: ΔH = -5.0 kcal/mol
- Compound D: ΔH = +4.5 kcal/mol

3. **Compare the Values**:
- We will compare the positive ΔH values since only those indicate heat absorption.
- From the example values:
- Compound A: +1.08 kcal/mol
- Compound B: +16.8 kcal/mol
- Compound C: -5.0 kcal/mol (discarded as it is negative)
- Compound D: +4.5 kcal/mol

4. **Identify the Maximum Value**:
- Among the positive values, +16.8 kcal/mol (Compound B) is the highest.

5. **Conclusion**:
- Therefore, the compound that will absorb the maximum amount of heat when dissolved in the same amount of water is Compound B, with ΔH = +16.8 kcal/mol.