MCQ
Which of the following statements is correct?
  • A
    The rate of a reaction decreases with passage of time as the concentration of reactants decreases.
  • B
    The rate of a reaction is same at any time during the reaction.
  • C
    The rate of a reaction is independent of temperature change.
  • D
    The rate of a reaction decreases with increase in concentration of reactant(s).

Answer

  1. The rate of a reaction decreases with passage of time as the concentration of reactants decreases.

Explanation:

The rate of a reaction can be defined as the change in concentration of a reactant of product in unit time. To be more specific, it can be expressed in term of:

  1. The rate of decrease in concentration of any one of the reactants, or
  2. The rate of increase in concentration of any one of the products. Concentration of reactant decreases with the passage of time, we can say that the rate is also decreasing.

$\text{r}=\frac{-\text{dx}}{\text{dt}}$ (r = rate)

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