IDENTIFYING THE Ni++ BASIC RADICAL PRESENT IN GIVEN INORGANIC SALT

Experiment 17: IDENTIFYING THE Ni++ BASIC RADICAL PRESENT IN GIVEN INORGANIC SALT

OBJECTIVE:

TO IDENTIFY THE BASIC RADICAL PRESENT IN GIVEN INORGANIC SALT

APPARATUS REQUIRED

• Test tube
• Test tube holder

CHEMICALS REQUIRED

• Dil. HCl
• H₂S
• NH₄OH
• NH₄Cl
• NaOH
• DMG

THEORY

Qualitative inorganic analysis is concerned with the detection and identification of radicals present in inorganic salt or a mixture of salts. Inorganic salts are the outcome of the neutralization of acids with base. Each inorganic salt consists of two parts. The part contributed by acid is called acid radical or anion and the part contributed by base is called basic radical or cation. For example, in sodium chloride, which can be obtained by the neutralization of base NaOH with acid HCl, Na⁺ is the basic radical and Cl^– is the acid radical.

PROCEDURE

The original solution was prepared by dissolving the given salt sample in water. The sample was subjected to several tests for the detection of the basic radical of the salt.

OBSERVATION

1. Preliminary test:

a. State: Solid
b. Odour: Odourless
c. Colour: Green
d. Solubility: Soluble in water

Group Separation Table

Experiment	Observation	Inference
1. 2 ml of the original solution was taken in a clean and dry test tube and a few drops of dil. HCl was added to it.	White ppt. is not formed.	Absence of Group I metal ions
2. The solution above was passed to the H2S solution.	No any ppt. was formed	Absence of Group II metal ions
3. 2 ml of the original solution was taken in a clean and dry test tube and a double volume of NH4Cl was added.	No any ppt. was formed	Absence of Group IIIA metal ions
4. The solution above in 3 was warmed and H2S was passed.	Black ppt. was formed.	Presence of Group IIIB metal ions

2. Confirmatory test:

Test of Ni⁺⁺ ion

Experiment	Observation	Inference
1. 2 ml of the original solution was taken in a clean and dry test tube and a few drops of NaOH solution were added to it.	Apple green ppt. was formed.	Presence of Ni++
2. 2 ml of the original solution was taken in a clean and dry test tube and a few drops of NH4OH solution were added.	Green ppt. was formed that dissolved in excess reagent giving a deep blue solution.	Presence of Ni++
3. 2 ml of the original solution was taken in a clean and dry test tube and a few drops of NH4OH solution and dimethyl glyoxime reagent (C4H8O2N2: DMG) were added to it.	Bright red ppt. was formed.	Presence of Ni++

Reactions involved:

RESULT

Hence, the sample was identified as Ni⁺⁺ basic radical.

CONCLUSION

Hence, we can test the basic radicals of a salt by wet ways testing the original solution with several reagents.

PRECAUTION

1. Concentrated solutions should be handled carefully.
2. The colour of the precipitate should be observed carefully.
3. Check whether the original solution is clear and transparent.