Chrominfo: Preparation and standardization of 0.1 M zinc chloride

Learn about the preparation and standardization of 0.1 M zinc chloride solution through a laboratory experiment or practical.

Aim:

To prepare and standardize 0.1 M zinc chloride solution using standard 0.1M EDTA (Complexometric titration).

Requirements:

Glasswares: Burette, burette stand, conical flask, volumetric pipette, beaker, volumetric flask, funnel, glass rod, and wash bottle, etc.

Chemicals: Zinc chloride (ZnCl2), disodium edetate (C10H16N2O8), ammonium acetate (C2H7NO2), hydrochloric acid (HCl), hexamine (C6H12N4) and xylenol orange indicator, etc.

Preparation of 0.1M zinc chloride solution:

Take properly weighed 13.63 gm of zinc chloride and dissolve in a minimum volume of 2M HCl, add 500 ml of distilled water and allow cooling and dissolving. Once it has completely dissolved, make up the volume to 1000 ml with water.

Preparation of 2M HCl:

Take 07.30 gm of concentrated hydrochloric acid in 1000 ml of distilled water.

Titration procedure:

All glassware should be cleaned and dried according to standard laboratory procedures.
Before filling the burette for the titration, rinse it with distilled water and then pre-rinse it with a portion of the titrant solution. Pre-rinsing is required to make sure that all solution in the burette is the desired solution, not a contaminated or diluted solution.
Take the unknown stock solution of titrant in a clean and dry beaker then fill the burette using the funnel.
Remove air bubbles from the burette and adjust the reading to zero.
Take 25.00 ml of a prepared 0.1 M zinc chloride solution and pour it into a conical flask.
Add 04.00 gm of ammonium acetate.
Then add 25.00 ml of distilled water and 50.00 mg xylenol orange mixture and shake well.
Add a sufficient amount of hexamethylenetetramine until the solution becomes violet-pink.
Titrate it with previously standardized 0.1 M Disodium edetate solution with constant stirring until the endpoint.
A solution becomes yellow when it reaches the endpoint.
To get accurate results, repeat the titration three times.
Properly record the readings of the burette.
Take their mean and calculate the molarity of the zinc chloride solution.

Observation table:

Sr. No.	Content in conical flask	Burette reading		Volume of titrant used (ml)
Sr. No.	Content in conical flask	Initial	Final	Volume of titrant used (ml)
1
2
3
				Mean:

Calculations:

1 ml of 0.1 M EDTA is equivalent to 0.013630 g of zinc chloride.

M = Molarity of EDTA x reading of the burette / 25

Result:

The strength of the prepared zinc chloride solution was found to be_____M.

Frequently Asked Questions (FAQ):

How to prepare 0.05 m zinc chloride solution?

Take properly weighed 6.82 gm of zinc chloride and pour in a 1-liter volumetric flask, add a minimum volume of 2M HCl to dissolve, and make up the volume to 1000 ml with water.