13. To analyse the acidic and basic radicals in the given salt (Pb(CH3COO)2).

Aim:- To analyse the acidic and basic radicals in the given salt.

Physical appearance:-

Colour: White

Smell: Odourless

Appearance: Amorphous

Dry heating test:-

Procedure	Observation	Inference
Take a small amount of the salt in a dry test tube and heat.	Brown when hot and yellow when cold.	Pb2+ may be present.

Flame test:-

Procedure	Observation	Inference
Prepare a paste of the salt with concentrated HCL on a clean watch glass. Place small amount of this paste on platinum wire loop and introduce it into the flame.	Colour of the flame turns dull bluish white.	Pb2+ may be present.

 

Concentrated sulfuric acid test:-

Procedure	Observation	Inference
Take a small amount of the salt in a test tube and add 1-2 ml of concentrated sulphuric acid.	No gas / vapours evolved	CH3COO- may be present.

Confirmation of acid radicals by wet test:-

Aqueous solution or water extract: Shake a little amount of the salt with water. If the salt dissolves, this aqueous solution obtained is used for the wet tests of acid radicals and is called water extract or 'W.E'.

Procedure	Observation	Inference
(i) Oxalic acid test:- Take a small quantity of the salt on a watch glass. Mix it with solid oxalic acid. Prepare paste of it with a few drops of water. Rub the paste and smell.	Smell like that of vinegar.	CH3COO- may be present.
(ii) Ester test:- take a small quantity of the salt in the test tube. Add concentrated H2SO4 (0.2 ml) and heat. Now add ethyl alcohol (1 ml). Shake and pour the contents of the tube in a beaker full of water and stir.	Pleasant fruity smell of ester.	CH3COO- is present.

Wet test for basic radicals (cations):-

Preparation of original solution: Take a small quantity of the given salt in a test tube and add some distilled water do it and shake the contents. If the salt does not dissolve, heat the content till the salt completely dissolves. The clean solution thus obtained is labelled as original solution (O.S).

Procedure	Observation	Inference
(i) Add dilute HCL to the original solution.	White precipitate is formed.	Pb2+ may be present.
(ii) Potassium iodide test:- to the one part add KI solution.	Yellow precipitate is formed.	Pb2+ is present.
(iii) Potassium chromate test:- To the other part add K2CrO4 solution.	Yellow precipitate is formed.	Pb2+ is present.

Result:-

Acid Radical: CH₃COO^-

Basic Radical: Pb²⁺

Therefore, The salt is Pb(CH₃COO)₂.