The amount of heat evolved when 0.50 mole of HCl is mixed with 0.30 mole of NaOH solution is

Options

A. 57.1 kJ
B. 28.55 kJ
C. 11.42 kJ
D. 17.13 kJ

Explanation

To find the amount of heat evolved when 0.50 moles of HCl are mixed with 0.30 moles of NaOH, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction**:
The reaction between HCl (a strong acid) and NaOH (a strong base) is a neutralization reaction. The products of this reaction are salt (NaCl) and water (H2O).

\[ \text{HCl} + \text{NaOH} \rightarrow \text{NaCl} + \text{H}_2\text{O} \]

2. **Determine the Limiting Reagent**:
We have 0.50 moles of HCl and 0.30 moles of NaOH. In a 1:1 stoichiometric reaction, NaOH is the limiting reagent because it is present in a smaller amount (0.30 moles).

3. **Calculate the Heat Evolved**:
The heat evolved during the neutralization reaction is given by the enthalpy change (ΔH) of the reaction. The standard ΔH for the neutralization of a strong acid with a strong base is approximately -57.1 kJ per mole of reaction.

Since NaOH is the limiting reagent, we will use its amount to calculate the heat evolved:
\[ \text{Heat evolved} = \Delta H \times \text{moles of limiting reagent} \]
\[ \text{Heat evolved} = -57.1 \, \text{kJ/mol} \times 0.30 \, \text{mol} \]

4. **Perform the Calculation**:
\[ \text{Heat evolved} = -57.1 \times 0.30 = -17.13 \, \text{kJ} \]

5. **Final Answer**:
The amount of heat evolved when 0.50 moles of HCl are mixed with 0.30 moles of NaOH is -17.13 kJ. The negative sign indicates that heat is released in the reaction.

### Summary:
The heat evolved is -17.13 kJ, and we typically report the magnitude when discussing heat evolved in exothermic reactions, so the answer is 17.13 kJ.

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