Select the correct answer.

Consider these two statements regarding the equation [tex]PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g) + \text{heat}[/tex]:

Statement 1: Adding heat to this reaction mixture would increase the reverse reaction.
Statement 2: Cooling this reaction mixture would increase the forward reaction.

A. Statements 1 and 2 are both true.
B. Statement 1 is true, and statement 2 is false.
C. Statements 1 and 2 are both false.
D. Statement 1 is false, and statement 2 is true.



Answer :

To solve this, we'll analyze the equilibrium reaction [tex]\(PCl_5(g) \rightleftharpoons PCl_3(g) + Cl_2(g) + \text{heat}\)[/tex] using Le Chatelier’s Principle.

Le Chatelier’s Principle states that if a dynamic equilibrium is disturbed by changing the conditions, the position of equilibrium moves to counteract the change.

### Statement 1: Adding heat to this reaction mixture would increase the reverse reaction.
- In the given equilibrium, heat is a product of the forward reaction.
- Adding heat to the system means increasing the concentration of heat, which is akin to adding more product.
- According to Le Chatelier’s Principle, the equilibrium will shift to the left to consume the added heat, favoring the reverse reaction to produce more [tex]\(PCl_5\)[/tex].
- Therefore, Statement 1 is true.

### Statement 2: Cooling this reaction mixture would increase the forward reaction.
- Cooling the reaction mixture is effectively removing heat from the system.
- By removing heat, we’re reducing the concentration of one of the products.
- Le Chatelier’s Principle indicates that the system will shift to the right to produce more heat (and more products, [tex]\(PCl_3\)[/tex] and [tex]\(Cl_2\)[/tex]), thus favoring the forward reaction.
- Therefore, Statement 2 is true.

Based on this analysis:
- Both statements 1 and 2 are true.

### Conclusion:
The correct answer is:

A. Statements 1 and 2 are both true.