Question

Consider the reaction, A $\to$ B. The rate of reaction = $-\frac{d\left[A\right]}{dt}.$ Which of the following statement(s) define the negative sign used in the rate of the given reaction?

• A. The concentration of A remains constant.
• B. Increase in the concentration of A with time.
• C. Decrease in the concentration of A with time.
• D. The concentration of A is zero.

Answer 1

The correct option is C

Decrease in the concentration of A with time.

The rate of chemical reaction is defined as the change in concentration of any one of the reactants or products per unit time.

Consider the reaction: A $\to$ B,

The rate of the reaction is given by,

Rate = $-\frac{d\left[A\right]}{dt}=+\frac{d\left[B\right]}{dt}.$

Where, [A] $\to$ concentration of reactant A

[B] $\to$ concentration of product B

(-) Negative sign indicates the decrease in concentration of A with time.

(+) Positive sign indicates an increase in concentration of B with time.