In which of the following reaction the physical state of the reactants or the product is not correctly represented?

The correct option is D

${\text{NH}}_3\text{(s)}+\text{HCl (aq)}\leftrightharpoons {\text{NH}}_4\text{Cl (s)}$

While writing a chemical equation letter are used in brackets or subscripts next to the chemical formulae to specify the physical state of the reactants and the products.

- s is for solids

- l is for liquids

- g for gas

- aq is aqueous solution

The reaction in which the physical state of the reactants or the product is not correctly represented is:

${\text{NH}}_3\text{(s)}+\text{HCl (aq)}\leftrightharpoons {\text{NH}}_4\text{Cl (s)}$

This is because ammonia $\text{(}{NH}_3)$ is a gas.