If `HA+NaOH rarr NaA+H_(2)O" "DeltaH=-12kcal`
and `HB+NaOH rarr NaB+H_(2)O" " DeltaH=-11kcal`
then equimolar solution of which acid has higher `pH :`

Options

A. `HA`
B. `HB`
C. both have same `pH`
D. information insufficient

Explanation

To determine which equimolar solution of the acids HA or HB has a higher pH, we can follow these steps:

### Step 1: Understand the Neutralization Reactions
The reactions given are:
1. \( HA + NaOH \rightarrow NaA + H_2O \) with \( \Delta H = -12 \, \text{kcal} \)
2. \( HB + NaOH \rightarrow NaB + H_2O \) with \( \Delta H = -11 \, \text{kcal} \)

Both reactions are exothermic, meaning they release heat.

### Step 2: Analyze the Enthalpy Changes
The enthalpy change (\( \Delta H \)) indicates the strength of the acids:
- A more negative \( \Delta H \) value suggests a stronger acid because it releases more energy during the neutralization.
- Here, \( | \Delta H_1 | = 12 \, \text{kcal} \) for HA and \( | \Delta H_2 | = 11 \, \text{kcal} \) for HB.

### Step 3: Compare the Strength of the Acids
Since \( HA \) has a larger \( \Delta H \) (more negative), it is a stronger acid compared to \( HB \):
- \( HA \) is stronger than \( HB \).

### Step 4: Relate Acid Strength to pH
The pH of a solution is inversely related to the strength of the acid:
- Stronger acids produce more \( H^+ \) ions in solution, resulting in a lower pH.
- Conversely, weaker acids produce fewer \( H^+ \) ions, resulting in a higher pH.

### Step 5: Determine the pH of the Solutions
Since \( HA \) is stronger than \( HB \):
- \( HA \) will have a lower pH.
- \( HB \) will have a higher pH.

### Conclusion
The equimolar solution of \( HB \) has a higher pH compared to \( HA \).

### Final Answer
**The equimolar solution of acid \( HB \) has a higher pH.**

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