Define the rate of reaction.

The rate of reaction is defined as the change in concentration of a reactant or product per unit time. It indicates how fast a reaction proceeds.

For a general reaction $R \to P$, the rate of reaction can be expressed as:

where $[R]$ is the concentration of reactant, $[P]$ is the concentration of product, and $t$ is time. The negative sign for reactants indicates a decrease in concentration.

The unit of concentration is typically $\text{mol L}^{-1}$ (moles per liter) or M (molar), and the unit of time is usually seconds ($\text{s}$).
Therefore, the unit of the rate of reaction is:

Alternatively, it can be written as $\text{M s}^{-1}$.

अभिक्रिया का वेग वह दर है जिस पर समय के साथ अभिकारकों या उत्पादों की सांद्रता में परिवर्तन होता है। यह दर्शाता है कि कोई अभिक्रिया कितनी तेजी से आगे बढ़ती है।
इसका मात्रक $\text{mol L}^{-1} \text{ s}^{-1}$ होता है।