The reaction `A to C` has activation energy for the forward and the backward reaction has 25 kJ and 32 KJ respectively. The `DeltaH` for the reaction is

Options

A. 57 KJ
B. `-57 KJ`
C. 7 KJ
D. `-7 KJ`

Explanation

To find the value of ΔH for the reaction A to C, we can use the relationship between the activation energies of the forward and backward reactions. Here’s the step-by-step solution:

### Step 1: Identify the Given Data
We are given:
- Activation energy for the forward reaction (Ea, forward) = 25 kJ
- Activation energy for the backward reaction (Ea, backward) = 32 kJ

### Step 2: Understand the Relationship Between Activation Energies and ΔH
For an exothermic reaction, the relationship between the activation energies and the enthalpy change (ΔH) can be expressed as:
\[ Ea, \text{backward} = Ea, \text{forward} + ΔH \]
This means that the activation energy for the backward reaction is equal to the activation energy for the forward reaction plus the enthalpy change of the reaction.

### Step 3: Rearrange the Equation to Solve for ΔH
We can rearrange the equation to find ΔH:
\[ ΔH = Ea, \text{backward} - Ea, \text{forward} \]

### Step 4: Substitute the Values
Now, substituting the given values into the equation:
\[ ΔH = 32 \text{ kJ} - 25 \text{ kJ} \]

### Step 5: Calculate ΔH
Now, perform the calculation:
\[ ΔH = 32 - 25 = 7 \text{ kJ} \]

### Conclusion
The value of ΔH for the reaction A to C is **7 kJ**.

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