How is rate of reaction measured experimentally?

The rate of reaction is measured experimentally by monitoring the change in concentration of reactants or products over time.

In more detail, the rate of a chemical reaction is defined as the change in concentration of a reactant or product per unit time. This can be measured in several ways, depending on the nature of the reaction and the substances involved.

One common method is to measure the decrease in concentration of a reactant. This can be done by taking samples at regular intervals and analysing them using techniques such as titration or spectroscopy. For example, in a reaction involving a coloured reactant, the change in colour intensity can be measured using a colorimeter, which gives a measure of the concentration of the reactant.

Alternatively, the increase in concentration of a product can be monitored. This can be done using similar techniques to those used for measuring reactants. For instance, if a gas is produced in a reaction, the volume of gas produced can be measured over time using a gas syringe or manometer.

In some cases, indirect methods may be used to measure the rate of reaction. For example, if a reaction is exothermic (releases heat), the rate of reaction can be determined by measuring the rate of temperature increase in the reaction mixture.

It's important to note that the rate of reaction is not constant but changes as the reaction proceeds. This is because the rate depends on the concentrations of the reactants, which decrease as the reaction proceeds. Therefore, the rate of reaction is usually highest at the start of the reaction and decreases over time.

In order to obtain accurate results, it's crucial to control all other variables that could affect the rate of reaction, such as temperature, pressure, and the presence of catalysts. This ensures that any changes observed are due to changes in the concentration of reactants or products, and not due to other factors.

In conclusion, measuring the rate of reaction involves monitoring the change in concentration of reactants or products over time, using a variety of experimental techniques.