Question

How do you calculate the rate of reaction?

Answer 1

Hint The rate of the reaction is dependent on concentration. The rate of a reaction is the speed at which the chemical reaction takes place.

Complete step by step solution:
So in the question it is asked how we will find the rate of reaction, it's quite a vague question. We are familiar with the word rate which usually refers to speed. Here the question is about the rate of reaction i.e. the speed of the chemical reaction.
We know that in a chemical reaction a reactant is undergoing the change under suitable reaction conditions and finally yields the products
Here we have to know the rate or speed at which the chemical reaction is happening i.e. the reactant is getting converted into a product. From this statement we could have an idea that so everything that rate is dependent is on the concentration terms of the reactants or the concentration of the products.
Thereby we can conclude that we could measure the rate of reaction if we observe the concentration terms and the time taken.
For more clarity let’s explain the concept with an example.
Consider any substance A is converting to a product B.
Write the equation for the change,
$A\rightleftharpoons B$
Here we could write the equation for rate of reaction as,
$rate=\dfrac{-\left[ \Delta A \right]}{\left[ \Delta t \right]}=\dfrac{\left[ \Delta B \right]}{\left[ \Delta t \right]}$
Here the rate is expressed in two ways,
-In a way in which we have taken the concentration of the formation of the product B over a time t, to measure the rate.
-The another way is in which we have taken the rate of reaction of A and the diminishing rate of A as the rate .Since the concentration of the A is decreasing a negative sign is used to denote the same.

Note: If in a reaction equation coefficients are involved then we will divide the rate of the formation of diminishing of the species with respect to the coefficient term for those species.
Coefficients are those numerical digits that are inserted in a chemical equation to get a balanced equation.
Example if a chemical reaction take place between A and B and C and D is formed and the balanced chemical equation of their reaction have the coefficient terms then we write the equation for rate as,
$aA+bB\to cC+dD$
$Rate\,of\,reaction=\dfrac{-1}{a}\dfrac{\left[ \Delta A \right]}{\left[ \Delta t \right]}=\dfrac{-1}{b}\dfrac{\left[ \Delta B \right]}{\left[ \Delta t \right]}=\dfrac{1}{c}\dfrac{\left[ \Delta C \right]}{\left[ \Delta t \right]}=\dfrac{1}{d}\dfrac{\left[ \Delta D \right]}{\left[ \Delta t \right]}$