Titration

Titration is the slow addition of one solution of a known concentration (called a titrant) to a known volume of another solution of an unknown concentration.

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1. Titrant: The unknown solution taken in a Burette is called Titrant.
2. Titrand: The definite volume of standard solution taken in the filtration flask is called titrand.
3. Titration: The process of determination of the strength of an unknown solution with the help of a standard solution by using a suitable indicator is called filtration.
4. Endpoint or neutral point: The completion of the reaction shown by the indicator by its color change is called neutral point or endpoint
5. Equivalence point or theoretical endpoint: The point at which an equivalent point pipette of titrant added to the titrand is called equivalence point or theoretical endpoint.
6. Titration error: The difference between the equivalence point and end pointer neutral point is called titration error.
7. Indicator: The chemical substance which is one to detect the endpoint or neutral point and also use to find whether the substance or acidic, basic, or neutral.

In the lab mainly three types of indicators are used:-

• Litmus paper
• Methyl orange
• Phenolphthalein

Normality equation:-

V1S1 = V2S2 or V1N1 = V2N2 or VASA = VBSB

According to the law of equivalent, at the equivalence point.

No of gram equivalent of acid= no. of gram equivalent of base

Normality of a solution is defined as:-

Normality = No. of gram equivalent of solute / volume in a liter of a solution

Normality=No.of gram equivalent of solute/volume in a liter of a solutionNormality=No.ofgramequivalentofsolute/volumeinaliterofasolution

Therefore, no. of gram equivalent of solute = normality volume in a lit of soln.

At the equivalent of point,

No. of gm equivalent of acid = no. of gram equivalent of base.

or, Normality of acid × volume in l of acid = Normality of base × volume in a liter of base

or, Normality of acid × 1000 × volume in ml of acid = Normality of base × 1000 × volume in ml of base

or, Normality of acid × volume in ml of acid = Normality of base × volume in ml of base

or, N1 V1 = N2 V2 ……………… (i)

or, S1 V1 = S2 V2 ……………….(ii)

or, SA VA = SB VB ………………..(iii)

where,

N1 = Normality of acid

V1 = Volume of acid

N2 = Normality of base

V2 = Volume of base

SA = Strength of acid

SB = Strength of base

Eqn (i), (ii), and (iii) are the general forms of the Normality equation.