Question

What is formality? Explain with examples.

Answer 1

The number of gram formula masses of the ionic solute dissolved per litre of solution is known as the formality of the solution. It is symbolised by $F$. The term formality is commonly used to describe the concentration of ionic solids, which are made up of a network of ions rather than molecules. Formal solution is a solution with a formality of one and contains one gramme formula mass of solute per litre of solution.

Complete answer:
Moles of solute per litre of solution are expressed by both molarity and formality. The overall concentration of a material in solution, regardless of its chemical structure, is known as formality. When $0.1{\text{ }}mol$ of $NaCl$ is dissolved in $1{\text{ }}L$ of water, the result is a solution containing $0.1{\text{ }}mol$ of $N{a^ + }\,and{\text{ }}0.1$ mol of $C{l^ - }$. Because there is basically no undissociated $NaCl$ in solution, the molarity of$NaCl{\text{ }}is{\text{ }}0$. Instead, the solution is $0.1{\text{ }}M{\text{ }}Na + {\text{ }}and{\text{ }}0.1{\text{ }}M{\text{ }}Cl-.{\text{ }}NaCl$, on the other hand, has a formality of $0.1{\text{ }}F$.
The number of formula masses of any solute dissolved in $1{\text{ }}litre$ is the formality of the solution.

Note:
Let us know some more things about formality. The concentration of a specific chemical species is referred to as molarity. Formality, on the other hand, is the overall concentration of a substance, regardless of its chemical form. If a chemical dissolves without dissociating into ions, its molarity and formality are irrelevant.