Please note that (1+5); which should preferably read (1 V + 5 V), refers to the formulation of the dilute acid by mixing a volume (1 V) of conc. commercial nitric acid with 5 V of the solvent, in principle water. For mixtures/solutions of 2-components, formulations are more commonly given in terms of the corresponding formulation ratio (1 V : 5 V), while the components should be unambiguously identified (e.g. 1 V : 5 V; conc. HNO3 : H2O).

% (v/v) may possibly either refer to:

(i) volumetric percentage concentration, i.e. volume of the used commercial conc. acid : volume of solution (x100% v/v); or to

(ii) percentage formulation ratio, meaning, volume of the used commercial conc. acid : volume of water (x100% v/v).

The label concentration for the conc. commercial nitric acid shoud be read as wt%; meaning, (mass of pure nitric acid / mass of aq. solution)·100%.

The density should be available from the label.

Further note that concentrations are typically given in a solute to solution basis; not in a solute to solvent basis. A rare exception is molality (mol solute / kg solvent).

Dear Abed Lina

I agree with Carlos Araújo Queiroz . He is right this ratio is the volume dilution ratio in water. You have to use pure water. Then if prepare 120 ml of diluted acid

you 120/6=20 ml of concentrated nitric acid to 100 ml of pure water.

In the mixing process you have to add the acid slowly to the water and not the reverse.

Best wishes

Carlos Araújo Queiroz thank you so much that was very helpful

Abdelhalim abdelnaby Zekry thank you very much

it's clear to me now i appreciate your time