What will be the melting point of KCl if enthalpy change for the reaction is `"7.25 J mol"^(-1)` and entropy change is `"0.007 J K"^(-1)"mol"^(-1)`?

Options

A. 1835.2 K
B. 173 K
C. 1035.7 K
D. 1285.2 K

Explanation

To find the melting point of KCl using the given enthalpy change (ΔH) and entropy change (ΔS), we can apply the Gibbs free energy equation:

\[ \Delta G = \Delta H - T \Delta S \]

At the melting point, the system is in equilibrium, and thus the change in Gibbs free energy (ΔG) is zero:

\[ 0 = \Delta H - T \Delta S \]

From this, we can rearrange the equation to solve for the temperature (T):

\[ T = \frac{\Delta H}{\Delta S} \]

### Step 1: Identify the given values
- Enthalpy change (ΔH) = 7.25 J/mol
- Entropy change (ΔS) = 0.007 J/K·mol

### Step 2: Substitute the values into the equation
\[ T = \frac{7.25 \, \text{J/mol}}{0.007 \, \text{J/K·mol}} \]

### Step 3: Perform the calculation
\[ T = \frac{7.25}{0.007} \]

Calculating this gives:

\[ T = 1035.71 \, \text{K} \]

### Step 4: Round the answer
The melting point of KCl is approximately:

\[ T \approx 1036 \, \text{K} \]

### Final Answer
The melting point of KCl is approximately **1036 K**.

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