Question

Consider the given figure and choose the correct option:

• A. Activation energy of both forward and backward reaction is \( E_1 + E_2 \) and reactant is more stable than product.
• B. Activation energy of backward reaction is \( E_1 \) and product is more stable than reactant.
• C. Activation energy of forward reaction is \( E_1 + E_2 \) and product is less stable than reactant.
• D. Activation energy of forward reaction is \( E_1 + E_2 \) and product is more stable than reactant.

Hint:

In energy diagrams, the activation energy for the forward reaction is measured from the reactant to the activated complex, and the activation energy for the reverse reaction is measured from the product to the activated complex.

Answer 1

The Correct Option is D

The provided diagram illustrates a standard energy profile diagram for a chemical reaction, depicting the energy levels of reactants, products, and the activated complex (transition state). Two energy distinctions are identified:

• E₁: Represents the energy differential between the product and the activated complex.
• E₂: Represents the energy differential between the reactant and the product.

1. Forward Activation Energy

The forward activation energy quantifies the energy required for the conversion of reactants into the activated complex. This is equivalent to the total vertical energy difference from the reactant energy level to the peak of the curve.

Reactant → Product = E₂
Product → Activated complex = E₁
Consequently, forward activation energy = E₁ + E₂

2. Backward Activation Energy

The backward activation energy is the energy demand for the reverse reaction (product → activated complex). This value corresponds directly to the energy gap between the product and the activated complex:

Backward activation energy = E₁

3. Stability Comparison: Reactant vs. Product

Stability is inversely proportional to energy: a species with lower energy exhibits greater stability.

According to the diagram, the product resides at a higher energy level compared to the reactant. This indicates that the product is less stable, while the reactant is more stable.

Summary of Findings

• Forward activation energy = E₁ + E₂
• The product demonstrates less stability relative to the reactant

These conclusions align precisely with the assertions in Option 3.

Identified Correct Answer: Option 3