Question

Explain reaction rate with definition.

Answer 1

Reaction Rate: The reaction rate is defined as the change in the concentration of a reactant or product in a unit time.

For a general reaction: $\mathrm{aA}+\mathrm{bB}\to \mathrm{pP}+\mathrm{qQ}$

• In this reaction, ‘A’ and ‘B’ denote reactants, and ‘P’ and ‘Q’ denote products, while small letters ‘a’ and ‘b’ denote stoichiometric coefficients.

$\mathrm{r}=-\frac{1}{\mathrm{a}}\frac{-\mathrm{d}\left[\mathrm{A}\right]}{\mathrm{dt}}=-\frac{1}{\mathrm{b}}\frac{\mathrm{d}\left[\mathrm{B}\right]}{\mathrm{dt}}=\frac{1}{\mathrm{p}}\frac{\mathrm{d}\left[\mathrm{P}\right]}{\mathrm{dt}}=\frac{1}{\mathrm{q}}\frac{\mathrm{d}\left[\mathrm{Q}\right]}{\mathrm{dt}}$

• Here, the negative sign is used to indicate the decreasing concentration of the reactant and gave a positive value of rate.
• The unit of rate are mol L^-1 s^-1(Liquid reaction)or atm^-1 s^-1(gaseous reaction)