Question

The rate of a reaction expressed in terms of change in concentration of products at two different times, that is the average rate in terms of product, can be written as ?

• A. $\frac{x_2-x_1}{t_2-t_1}$
• B. $+$$\Delta x$$/$$\Delta t$
• C. $-$$\frac{x_2-x_1}{t_2-t_1}$
• D. $-$$\Delta x$$/$$\Delta t$

Answer 1

Answer: (A), (B)

The correct options are
A $\frac{x_2-x_1}{t_2-t_1}$
B $+$$\Delta x$$/$$\Delta t$

Concentration of product increases with time, unlike reactants. If $x_2$ and $x_1$ are the concentrations of product at time $t_2$ and $t_1$. Here, $x_2$ is greater than $x_1$ since it is a product. Thus, average rate is written as $\frac{x_2-x_1}{t_2-t_1}$, which is a positive quantity, since $x_2$ is greater than $x_1$. It can also be written as $+$$\Delta x$$/$$\Delta t$