To detect the acid and basic radicals in given salt (In Ammonium Phosphate).

Experiment – 7

Class – XII

Subject – Chemistry

Aim:-

To detect the acid and basic radicals in given salt (In Ammonium Phosphate).

Apparatus:-

Test tube, test tube stand, test tube holder, burner, beaker, litmus paper, match box etc.

Physical Characteristic:-

1.     State: - solid crystalline

2.     Color:- Colorless

3.     Odour:- ammonia smell

4.     Solubility:-  Soluble in cold water

Detection of Acid Radicals

Sr. No	Experiment	Observation	Inference
1.	Heating with dil. H2So4 ­to he pinch of salt dil. H2So4.	No gas evolved	Co3-, So32-, S2- No2-  ions absent
2.	Conc. H2So4 test The salt was heated with conc. H2So4 .	No gas evolved	Cl-, Br-, I-, No3-, CH3COO-  absent
3.	Ammonium Molybate test To the given salt conc. HNo3 was added then boiled. Then excess amount of ammonium molybate was added to solution.	Yellow PPT was obtained	Po43-  ion confirmed
	K3 Po4 + 3 (NH4)3 Moo4  à    2 (NH4)3 Po4 + 3 K2 MOO4 K2 Moo4 2 HNo3  à    H2 Moo4 + 2 KNo3 H2 Moo4   à   Moo3 + H2O (NH4)3  Po4 + 12 Moo3 + 6 H2O  à   (NH4)3. Po4. 12 Moo3 + 6 H2O

 

Detection of Basic Radicals:-

Sr. No.	Experiment	Observation	Inference
a.	Heating effect:- The small amount of slat heated with NaOH.	Colourless gas with ammonical smell evolved.	NH4+ may be present.
b.	Confirmatory Test
(i)	Sodium Hydroxide test The salt was mixed with NaOH a glass rod dipped in HCl and brings at mouth of test tube.	White fumes of NH4Cl were evolved.	NH4+  Confirmed
	NH4 Cl + NaOH   à    NH3 + NaCl + H2O NH3 + HCl   à    HN4 Cl
(ii)	Detect. Nessler reagent test Salt was heated with NaOH and gas evolved was passed through Nessler reagent.	Red brown ppt was obtained	NH4+ confirmed
	K2 Hg I4  +  2 NH3   à   Hg NH3 I  + NH4 I (aq) + 2 KI Hg  NH3 I + H2O   à    Hg. NH2       +  NH4 I

 

Conclusion:-

On the basis of above test, we conclude that given salt contain.

Acid Radical :           Po₄^3-

Basic Radical:           NH₄⁺