For a reaction2A_2+ B_2→ 2A_2BThe reactant A will be consumed at:

The correct answer is Option (3) → double the rate at which B is consumed.

From the balanced equation:

$2A_2 + B_2 \rightarrow 2A_2B$

Rate relation based on stoichiometric coefficients:

$-\frac{1}{2} \frac{d[A_2]}{dt} = -\frac{1}{1} \frac{d[B_2]}{dt}$

Rewriting:

$\frac{d[A_2]}{dt} = 2 \times \frac{d[B_2]}{dt}$

This means $A_2$ is consumed twice as fast as $B_2$.

Hence, the correct option is: "double the rate at which B is consumed."

Golden Trick

For:
2A₂ + B₂ → 2A₂B

• A₂ coefficient = 2
• B₂ coefficient = 1

Rule:  Rate of consumption ∝ Coefficient

So,

• A₂ is used 2 times
• B₂ is used 1 time

 Therefore:
A₂ is consumed at double the rate of B₂