Question

The reaction was found to be second order with respect to the concentration of carbon monoxide. If the concentration of carbon monoxide is doubled, with everything else kept the same, the rate of reaction will:

• A. double
• B. remain unchanged
• C. triple
• D. increase by a factor of $4$

Answer 1

Answer: (D)

increase by a factor of $4$

According to the given question the reaction follows second order kinetics and there is only one reactant that is carbon monoxide, let us assume it as 'A'.

we know that for second order reaction,

$r=k[A{]}^2$

Thus any change in the concentration of carbon dioxide will have it's effect on the rate of the reaction.

Hence when the concentration of carbon monoxide is doubled, the rate of the reaction will be increased by four times as the reaction follows second order kinetics.

$\therefore r=k[2A{]}^2$

$\therefore r=4k{A}^2$

which is four times it's initial rate.

Therefore the correct answer is option (D).