For a general reactions
` 2A +B hArr C +3D , Delta H = + x kcal `
what is the effect of increase of pressure at equilirbrium?

Answer

To determine the effect of an increase in pressure on the equilibrium of the reaction \(2A + B \rightleftharpoons C + 3D\) with a given enthalpy change \(\Delta H = + x \, \text{kcal}\), we can follow these steps:

### Step 1: Identify the number of moles on each side of the reaction.
- On the reactant side, we have:
- \(2A\) contributes 2 moles.
- \(B\) contributes 1 mole.

Total moles on the reactant side = \(2 + 1 = 3\) moles.

- On the product side, we have:
- \(C\) contributes 1 mole.
- \(3D\) contributes 3 moles.

Total moles on the product side = \(1 + 3 = 4\) moles.

### Step 2: Apply Le Chatelier's Principle.
Le Chatelier's Principle states that if an external change is applied to a system at equilibrium, the system will adjust itself to counteract that change. In this case, we are increasing the pressure.

### Step 3: Determine the direction of the shift.
- Since increasing pressure favors the side with fewer moles of gas, we compare the total moles:
- Reactants: 3 moles
- Products: 4 moles

- Since the reactants have fewer moles (3 moles) compared to the products (4 moles), the equilibrium will shift towards the side with fewer moles when pressure is increased.

### Step 4: Conclusion.
The equilibrium will shift to the left (towards the reactants) when the pressure is increased because the reactants have a lesser number of moles compared to the products.

### Final Answer:
When the pressure is increased, the equilibrium of the reaction \(2A + B \rightleftharpoons C + 3D\) will shift towards the left, favoring the formation of the reactants.

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