From the reaction P(White) `rarr` P(Red) `Delta H =-18.4KJ`, it follows that :-

Options

A. Red P is readily formed from white P
B. White P is readilly formed from red P
C. White P can not be converted to red P
D. White P can be converted into red P and red P is more stable

Answer

To solve the question regarding the reaction of white phosphorus (P) converting to red phosphorus (P) with a given enthalpy change (ΔH = -18.4 kJ), we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Reaction Type**:
The reaction given is:
\[ \text{P (White)} \rightarrow \text{P (Red)} \]
The negative ΔH value indicates that this reaction is exothermic.

**Hint**: Recall that an exothermic reaction releases heat, which is indicated by a negative ΔH.

2. **Understand ΔH**:
The enthalpy change (ΔH) of -18.4 kJ means that when 1 mole of white phosphorus is converted to red phosphorus, 18.4 kJ of energy is released.

**Hint**: Remember that a negative ΔH signifies that the products have lower energy than the reactants.

3. **Stability of Products**:
Since the reaction is exothermic, it suggests that the products (red phosphorus) are more stable than the reactants (white phosphorus). This is because the system releases energy when moving to a more stable state.

**Hint**: Consider the relationship between energy and stability; lower energy typically corresponds to greater stability.

4. **Conclusion**:
Based on the above points, we can conclude that red phosphorus is more stable than white phosphorus due to the release of energy during the conversion.

**Hint**: Think about how stability relates to energy levels in chemical reactions.

5. **Evaluate Options**:
If options A, B, and C are incorrect based on the reasoning, then option D must be correct, which states that red phosphorus is more stable than white phosphorus.

**Hint**: Always check the implications of ΔH values when evaluating multiple-choice answers.

### Final Answer:
Red phosphorus is more stable than white phosphorus due to the exothermic nature of the reaction (ΔH = -18.4 kJ).