Normalidade

Concentration units

1-Normality of solution:-

Is defined as the number of grams-equivalent weight of solute per one liter of solution .

Molarities of solution :-

A molar solution contains one gram molecular weights of solute dissolved in sufficient amount of solvent to give 1 liter of solution .

Formality :- is the number of grams formula weight of solute per liter of solution. used for partial dissolved solutes (such as acetic acid , oxalic acid etc…)

Preparation of 1% w/v Na2CO3 solution

Weigh 1 gm of sodium carbonate using a watch glass, transfer it into a beaker, then add 50 ml. of distilled water(mix using a stirrer )transfer the solution into a volumetric flask of 100 ml. add distilled water to the mark.

Mix the solution by inverting the flask 2-3 times to mix the component .

Q / prepare 0.3 % solution from 1% solution in 250 ml volumetric flask.

Preparation of 0.1N Na2CO3 solution

Weigh 1.325 gm of Na2CO3 (using a watch glass ) transfer it into a beaker. Add 100 ml of distilled water (using a stirrer to mix), after dissolving , transfer the solution into a volumetric flask of 250 ml then add water to the mark .

Q / From this solution prepare 0.05 N , and 0.02 N solution in 250 ml distill water ?

To prepare dilute solution from stock solution , this law must be used :-

Dilution law is :- (N x V)1 = (N x V)2

Where (1) refer to the concentrated solution and (2) refer to the diluted solution.

To find the normality of concentrated solutions (for liquid only) this law must be used:-

Or :

Q / prepare 2N solution in 250 ml volumetric flask from 5N of HCl stock solution .

Q / prepare 500 ml , 5N H2SO4 solution from original concentrated solution. .

Preparation of 0.1 M Na2CO3 solution in 250 ml D.W

Weight 2.65 gm of Na2CO3 , transfer it into a beaker. Add 100ml of D.W ( mix using a glass stirrer ).Transfer the solution into a 250 ml volumetric flask of, add water to the mark.

So : 1M Na2CO3 = 2N Na2CO3

part per million (PPm )

The concentration of very diluted solutions ,It’s the number of mg of salt dissolved in one liter solution.

Buffer solution

Any solution that contains both a weak acid and it’s weak base, has the ability to absorb small amounts of either a strong acid or strong base are added they are neutralized by the weak base , while small quantities of a strong base are neutralized by the weak acid, such solution are said to be buffer because they resist significant change in the PH .The PH value is determined by a PH meter.

Using of indicators in a PH estimation:-

Principle:-

A set of buffer solution of known PH is prepared form citric

...