14. Estimation of nickel in steel by EDTA method

14. ESTIMATION OF NICKEL IN STEEL BY EDTA METHOD

Expt. No.

Date:

AIM

To estimate the amount of nickel present in the given steel solution by EDTA method. You are provided with standard solution of zinc sulphate and EDTA as link solution.

CHEMICAL REQUIRED

1. EDTA 2. Fast sulphone black-F and muroxide indicators 3. Ammonium chloride 4. Ammonium hydroxide 5. Pure and dry zinc sulphate 6. Nickel sulphate.

PRINCIPLE

The nickel ions are determined using EDTA in the presence of muroxide indicator.

PROCEDURE

Titration I: Standardisation of EDTA

The burette is washed well with distilled water and then rinsed with a little amount of the given EDTA solution. It is then filled with the same solution upto zero level without air bubbles. 20 ml of the given standard ZnSO4 solution is pipetted out into a clean conical flask. 10 ml of ammonia buffer solution and 2 drops of muroxide indicator are added.

The solution turns yellow colour and it is then titrated against EDTA taken in the burette. The end point is the colour change from yellow colour to violet colour. The titration is repeated to get concordant values. From the volume of EDTA consumed, the strength of EDTA solution is calculated.

Titration II: Estimation of Nickel

EDTA Vs Nickel solution Indicator - Muroxie

Calculation

Volume of EDTA  V₁ = ...... ml

Strength of EDTA  N₁ = ...... N

Volume of nickel solution V₂ = 20 ml

Strength of nickel solution N₂ = .........

According to the law of volumetric analysis

V₁N₁ = V₂N₂

N₂ = V₁ × N₁ / V₂

Strength of nickel solution   N₂ = ...... N

Calculation of amount of the nickel

Amount of nickel present in the whole of the given solution = Eq. wt of nickel × Strength of nickel solution

= 29.3 × ...... N

= ............ gms

Titration II: Estimation of nickel

The given nickel solution is made up to 100 ml in a standard measuring flask. 20 ml of this solution is pipetted out into a clean conical flask. 10 ml of ammonia buffer solution and 2 drops of muroxide indicator are added. The solution turns yellow in colour and it is then titrated against standardised EDTA taken in the burette. The colour change is from yellow to violet colour indicating the end point. The titration is repeated to get concordant values.

Equivalent weight of nickel = 29.3

RESULT

1. Amount of nickel present in the whole of the given solution = ………. Gms