Question

What are the demerits of the chemical equation?

Answer 1

Hint: We can tell the demerits or disadvantages of the chemical equation by the factors like concentration, temperature, pressure, actual yield, precipitate, enthalpy of the reaction, spontaneity of the reaction, kinetics of the reaction, etc.

Complete answer:
When some substances combine with each other to form a new substance, then it is known as a reaction. So, when they are written in the chemicals form, then it is a chemical equation. For example, when hydrochloric acid and sodium hydroxide reacts with each other then there is the formation of sodium chloride and water. The chemical equation is given below:
$HCl+NaOH\to NaCl+{{H}_{2}}O$
Chemical equations are very helpful but there are many demerits like:
The concentration of the reactants and products are not defined in the reaction.
At what temperature and pressure, the chemical reaction takes place is not defined in the equation.
By looking at the chemical equation, we cannot predict the actual yield of the products in the reaction.
The chemical equation cannot tell whether a catalyst is required in the reaction or not.
In some chemical reactions, there is the formation of precipitate and in some, there is an evolution of certain gases, but the equation these are not mentioned.
The enthalpy of the reaction is also not mentioned, i.e., whether the reaction is exothermic or endothermic.
In the chemical equation, we cannot predict the time in which the reaction will be completed and whether the reaction will occur on its own.

Note:
(s), (l), (aq), and (g) are written next to each compound in certain reactions, indicating that the compound is in solid, liquid, aqueous, or gaseous form, respectively. These are the physical states of the compound.