Chemistry Practical

Experiment1

Carbonate(CO₃)^2-

AIM: To identify the acid radical present in the given salt sample, (CO₃)^2-

(A) PHYSICAL CHARACTERISTICS:-

(i) Colour- white

(ii) Odour-odourless

(iii)State-crystalline

(iv) Solubility- soluble in water

(B) DRY TESTS FOR DETECTION OF ACID RADICALS:-

S.No	Experiment	Observation	Inference
			Gas evolved	Possible Radical
i	Dilute sulphuric acid test- A pinch of salt was taken in a clean dry test tube and 2-3 ml of dil. H2SO4 was added.	Colourless, odourless gas with brisk effervescence, turns lime water milky	CO2	CO3 2-

CHEMICAL REACTIONS INVOLVED:-

CO₃^2- + H₂ SO₄ → SO₄^2- + H₂O + CO₂↑

                                                       (brisk effervescence)

 (C) WET TESTS FOR CONFIRMATION OF ACID RADICAL:-

(i) Preparation of Original Solution- A little amount of salt was taken in a clean dry test tube to which 5 ml distilled water was added. The test tube was shaken till the salt dissolved and a clear solution was obtained. This clear solution is labelled as original solution(o.s)

	Experiment	Observation	Inference
(i)	Magnesium sulphate test: To a part of the aqueous solution, small quantity of 2-3 ml of magnesium sulphate solution was added.	White ppt. obtained	CO3 -2-confirmed

CHEMICAL REACTIONS INVOLVED:-

CO₃^2- + MgSO₄ → MgCO₃↓ + SO₄^2-

                               (white ppt)

(D) RESULT:- The given salt contains Carbonate (CO₃)^2- as the acid radical.

Experiment2

Sulphide, S^2-

AIM: To identify the acid radical present in the given salt sample, S^2-

(A) PHYSICAL CHARACTERISTICS:-

(i) Colour- pale yellow

(ii) Odour- rotten egg smell

(iii)State- amorphous, flaky

(iv) Solubility-soluble in water

(B) DRY TESTS FOR DETECTION OF ACID RADICALS:-

S.No	Experiment	Observation	Inference
			Gas evolved	Possible Radical
i	Dilute sulphuric acid test- A pinch of salt was taken in a clean dry test tube and 2-3 ml of dil. H2SO4 was added.	Colourless gas with rotten egg smell which turn lead acetate paper black	H2S	S2-

CHEMICAL REACTIONS INVOLVED:-

S^2- + H₂ SO₄ → SO₄^2- + H₂S ↑

                                        (rotten egg smell)

 (C) WET TESTS FOR CONFIRMATION OF ACID RADICAL:-

(i) Preparation of Original Solution- A little amount of salt was taken in a clean dry test tube to which 5 ml distilled water was added. The test tube was shaken till the salt dissolved and a clear solution was obtained. This clear solution is labelled as original solution(o.s)

	Experiment	Observation	Inference
(i)	Lead acetate test: To a part of the aqueous solution, small quantity of 2-3 ml of lead acetate solution was added.	Black  ppt. obtained	S-2-confirmed

CHEMICAL REACTIONS INVOLVED:-

S^2- + Pb(CH₃COO)₂→ PbS↓ +    2CH₃COO^-                         

                                 (black ppt)

(D)RESULT:- The given salt contains Sulphide, S^2- as the acid radical.

Experiment3

Nitrite, NO₂^-

AIM: To identify the acid radical present in the given salt sample, NO₂^-

(A) PHYSICAL CHARACTERISTICS:-

(i) Colour- white

(ii) Odour-odourless

(iii)State-crystalline

(iv) Solubility- soluble in water

(B) DRY TESTS FOR DETECTION OF ACID RADICALS:-

S.No	Experiment	Observation	Inference
			Gas evolved	Possible Radical
i	Dilute sulphuric acid test- A pinch of salt was taken in a clean dry test tube and 2-3 ml of dil. H2SO4 was added.	Reddish brown gas evolve which turn FeSO4 solution brown	NO2	NO2-

CHEMICAL REACTIONS INVOLVED:-

3NO₂^- + 3H₂ SO₄ → 3HSO₄^2- + HNO₃ + H₂O + 2NO

2NO + O₂     à     2NO₂

 (colourless)   (brown gas)

 (C) WET TESTS FOR CONFIRMATION OF ACID RADICAL:-

(i) Preparation of Original Solution- A little amount of salt was taken in a clean dry test tube to which 5 ml distilled water was added. The test tube was shaken till the salt dissolved and a clear solution was obtained. This clear solution is labelled as original solution(o.s)

	Experiment	Observation	Inference
(i)	Ferrous sulphate test: To a part of the aqueous solution, small quantity of dil acetic acid and ferrous sulphate solution was added.	Brown colouration obtained	NO2-confirmed

CHEMICAL REACTIONS INVOLVED:-

NO₂^- + CH₃COOH àCH3COO^-  + HNO₂

3HNO₂ àHNO₃ + 2NO + H₂O

FeSO₄ + NO à FeSO₄.NO

(D) RESULT:- The given salt contains Nitrite, NO₂^- as the acid radical.

AIM: To identify the acid radical present in the given salt sample.

(A) PHYSICAL CHARACTERISTICS:

Colour-White, Odour: odourless

State: crystalline, Solubility: soluble in water

 (B) DRY TESTS FOR ACID RADICALS:-

S.No	Experiment	Observation	Inference
i	Dilute sulphuric acid test – To a pinch of salt taken in a dry test tube, 1-2 ml of dil. H2SO4 was added.	No brisk effervescence	CO3 2- absent
		No gas with smell of burning sulphur	SO3 2- absent
		No gas with rotten egg smell	S 2- absent
		No reddish brown gas	NO2- absent
ii	Oxalic acid test- To a pinch of the salt taken on a watch glass, oxalic acid crystals and few drops of water were added to make a paste.	No smell of vinegar	CH3COO- absent
iii	MnO2 test- To a pinch of the salt taken in a dry test tube with equal amount of MnO2,1-2ml conc. H2SO4 was added and heated.	Deep violet vapours evolve which turn starch solution blue	The evolving gas is I2 and the presence of I- ion is indicated.

CHEMICAL REACTIONS INVOLVED:-

MnO₂  +  3H₂SO₄  +  2I^-  →  MnSO₄   + I₂ ↑  + 2HSO₄^-  +  2H₂O 

                                                                Deep violet vapours

 (C) WET TEST  FOR CONFIRMATION OF ACID RADICAL:-

(i) Preparation of original solution- A little amount of salt was taken in a clean dry test tube to which 5 ml distilled water was added. The test tube was shaken till the salt dissolved and a clear solution was obtained. This solution is labeled as original solution (o.s)

(ii) Confirmatory test of Iodide ion:

S.No	Experiment	Observation	Inference
i	Silver Nitrate test – To the os, AgNO3 solution is added.	A yellow ppt.is formed which is insoluble in NH4OH solution.	The presence of I- ion is confirmed.

CHEMICAL REACTIONS INVOLVED:-

AgNO₃ (aq)  +  Cl^- (aq)   →   AgI ↓  +  NO₃^-  

                                           yellow ppt.

(D) RESULT:- The acid radical present in the given sample is Iodide,I^-                                                                                      

Bromide,Br^-

AIM: To identify the acid radical present in the given salt sample.

(A) PHYSICAL CHARACTERISTICS:

Colour-White, Odour: odourless

State: crystalline, Solubility: soluble in water

 (B) DRY TESTS FOR ACID RADICALS:-

S.No	Experiment	Observation	Inference
i	Dilute sulphuric acid test – To a pinch of salt taken in a dry test tube, 1-2 ml of dil. H2SO4 was added.	No brisk effervescence	CO3 2- absent
		No gas with smell of burning sulphur	SO3 2- absent
		No gas with rotten egg smell	S 2- absent
		No reddish brown gas	NO2- absent
ii	Oxalic acid test- To a pinch of the salt taken on a watch glass, oxalic acid crystals and few drops of water were added to make a paste.	No smell of vinegar	CH3COO- absent
iii	MnO2 test- To a pinch of the salt taken in a dry test tube with equal amount of MnO2,1-2ml conc. H2SO4 was added and heated.	Reddish brown vapours evolve which turn starch solution yellow.	The evolving gas is Br2 and the presence of Br- ion is indicated.

CHEMICAL REACTIONS INVOLVED:-

MnO₂  +  3H₂SO₄  +  2 Br^-   →  MnSO₄   + Br₂ ↑  + 2HSO₄^-  +  2H₂O 

                                                                Reddish brown vapours

 (C) WET TEST  FOR CONFIRMATION OF ACID RADICAL:-

(i) Preparation of original solution- A little amount of salt was taken in a clean dry test tube to which 5 ml distilled water was added. The test tube was shaken till the salt dissolved and a clear solution was obtained. This solution is labeled as original solution (o.s)

(ii) Confirmatory test of Bromide ion:

S.No	Experiment	Observation	Inference
i	Silver Nitrate test – To the os, AgNO3 solution is added.	A pale yellow ppt. is formed which is sparingly soluble inNH4OH solution.	The presence of Br- ion is confirmed.

CHEMICAL REACTIONS INVOLVED:-

AgNO₃ (aq)  +  Br^- (aq)   →   AgBr ↓  +  NO₃^-  

                                           Pale yellow ppt.

 (D) RESULT:- The acid radical present in the given sample is Bromide,Br^-                     

Chloride,Cl^-

AIM: To identify the acid radical present in the given salt sample.

(A) PHYSICAL CHARACTERISTICS:

Colour-White, Odour: odourless

State: crystalline, Solubility: soluble in water

 (B) DRY TESTS FOR ACID RADICALS:-

S.No	Experiment	Observation	Inference
i	Dilute sulphuric acid test – To a pinch of salt taken in a dry test tube, 1-2 ml of dil. H2SO4 was added.	No brisk effervescence	CO3 2- absent
		No gas with smell of burning sulphur	SO3 2- absent
		No gas with rotten egg smell	S 2- absent
		No reddish brown gas	NO2- absent
ii	Oxalic acid test- To a pinch of the salt taken on a watch glass, oxalic acid crystals and few drops of water were added to make a paste.	No smell of vinegar	CH3COO- absent
iii	MnO2 test- To a pinch of the salt taken in a dry test tube with equal amount of MnO2,1-2ml conc. H2SO4 was added and heated.	A greenish yellow gas with pungent smell evolves which turn starch iodide paper blue	The evolving gas is Cl2 and the presence of Cl- ion is indicated.

CHEMICAL REACTIONS INVOLVED:-

MnO₂  +  3H₂SO₄  +  2Cl^-  →  MnSO₄   + Cl₂ ↑  + 2HSO₄^-  +  2H₂O 

                                                                Greenish yellow

                                                                        gas

 (C) WET TEST  FOR CONFIRMATION OF ACID RADICAL:-

(i) Preparation of original solution- A little amount of salt was taken in a clean dry test tube to which 5 ml distilled water was added. The test tube was shaken till the salt dissolved and a clear solution was obtained. This solution is labeled as original solution (o.s)

(ii) Confirmatory test of Chloride ion:

S.No	Experiment	Observation	Inference
i	Silver Nitrate test – To the os, AgNO3 solution is added.	A white ppt.is formed which is insoluble in HNO3 but soluble inNH4OH solution.	The presence of Cl- ion is confirmed.

CHEMICAL REACTIONS INVOLVED:-

AgNO₃ (aq)  +  Cl^- (aq)   →   AgCl ↓  +  NO₃^-  

                                           White ppt.

AgCl  +  NH₄OH   →  [Ag(NH₃)₂]Cl  +  2H₂O

                                      Soluble complex

(D) RESULT:- The acid radical present in the given sample is Chloride,Cl^-