1 : compliance with formal or conventional rules : ceremony. 2 : the quality or state of being formal. 3 : an established form or procedure that is required or conventional the interview was just a formality.
Formality is a substance's total concentration in solution without regard to its specific chemical form. For example, dissolving 0.1 mol of NaCl in 1 L of water gives a solution containing 0.1 mol of Na+ and 0.1 mol of Cl–.
I am so sorry if it’s wrong.