Popular Chemistry Online: October 2022

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Sunday, October 23, 2022

To analyse the given sample of salt for detection of one acidic and one basic radical

 Aim: - To analyse the given sample of salt for detection of one acidic and one basic radical

Observation table-

A) Detection of acidic  radical(anion)

S.N.

EXPERIMENT

OBSERVATION

INFERENCE

1

Salt solution + dil H2SO4

Colourless, colourless gas with brisk effervescence which turn lime

water milky

Group A anion (CO32- may be present)

2.

Confirmative test :

(a)  BaCl2 Test : Salt solution + BaCl2

 

(b)  MgSO4 Test : Salt solution + MgSO4

White ppt of BaCO


White ppt of MgCO3

CO32-Confirmed CO32- Confirmed

 

B. Detection of basic radical(cation)

S.N.

EXPERIMENT

OBSERVATION

INFERENCE

1

Salt + NaOH solution + heat

Colourless gas with

ammonical smell evolves

Zero group is

present NH4+ may be present

2.

Confirmatory test of  NH4+ :-

(a)  put glass rod dipped in conc. HCl acid on the mouth of test tube

(b)  Salt + conc. NaOH + Nessler reagent + Warm

 


Dense white fumes generate around glass rod


Brown solution

 

NH4+ Confirm 


NH4+ Confirm

 

Result: in given sample of salt on acidic radical carbonate (CO32-) and one basic radical ammonium (NH4+) is present.

To analyse the given sample of salt for detection of one acidic and one basic radical

Aim: - To analyse the given sample of salt for detection of one acidic and one basic radical

Observation table-

A) Detection of acidic  radical(anion)

S.N.

EXPERIMENT

OBSERVATION

INFERENCE

1

Salt + Dil. H2SO4 and warm solution

Colourless gas with vinegar like smell

evolves

Acetate (CH3COO-) may be present

2.

Confirmatory test for Acetate:

(a)  Oxalic acid test: take 1 g of salt in test tube and add small amount of oxalic acid + one -two drops of distilled water

 

(b)  Ferric Chloride test: take 1 g of salt in test tube and add 1-2 ml distilled water , shake well and add 1-2 ml of neutral ferric chloride

solution to it

 


Smell of vinegar obtained

 

 

 

Deep red color appears

 

Acetate (CH3COO-) is confirmed

 

 

 

Acetate (CH3COO-) is confirmed

 

Detection of basic radical(cation)

S.N.

EXPERIMENT

OBSERVATION

INFERENCE

1

Salt + NaOH solution + heat

No gas evolve

Zero group is absent

2.

Prepare original solution of salt by dissolving in 20 ml of water

Cleat solution is formed

Water soluble salt is present

3.

Small amount of OS + Dil. HCl

solution

White precipitate is

formed

Group -I is present

Pb2+ may be present

4.

Confirmatory test of Pb2+: dissolve the precipitate in hot water and divide it into three parts

(a)  part -1 + KI solution


(b)  part-2 + potassium chromate

 

(c)  part-3 + few drops of alcohol + dil. H2SO4

 

 

 

 Yellow precipitate 


yellow precipitate is obtained which is soluble in NaOH 


White precipitate is obtained which is

soluble in ammonium acetate

 

 

 

Pb2+ is confirmed 



Pb2+is confirmed

 



Pb2+ is confirmed

Result: in given sample of salt on acidic radical acetate (CH3COO-) and one basic radical lead (Pb2+) is present. 

To analyse the given sample of salt for detection of one acidic and one basic radical

Aim: - To analyse the given sample of salt for detection of one acidic and one basic radical

Observation table-

A) Detection of acidic  radical(anion)

S.N.

EXPERIMENT

OBSERVATION

INFERENCE

1

Salt + Dil. H2SO4

No gas evolves

SO44-group is absent

2.

Salt + Con. H2SO4

Colourless gas with

pungent smell evolves

Chloride (Cl-) may be present

3.

Confirmatory test for chloride:

(a)  Salt + Dil. HNO3 + AgNO3 solution

 


(b)  Chromyl  chloride test:-

·      Salt + K2Cr2O7 + Conc. H2SO4 + warm

 



·      Pass the vapours through NaOH solution



·      Add lead acetate and dil. Acetic acid to yellow solution

 

 

 

White ppt soluble in

Chloride (Cl-) is

 

ammonia solution

confirmed

 


 Red colour vapors evolves

 

Chloride (Cl-) may be

 


 

 

Solution turns

 

 

yellow         

Chloride (Cl-) is

 


Yellow precipitate is

confirmed

 

formed

 

 

Detection of basic radical(cation)

S.N.

EXPERIMENT

OBSERVATION

INFERENCE

1

Salt + NaOH solution + heat

Colourless gas with ammonical smell evolves

Zero group is

present NH4+ may be present

2.

Confirmatory test of  NH4+ :-

(a)  put glass rod dipped in conc. HCl acid on the mouth of test tube

(b)  Salt + conc. NaOH + Nessler reagent + Warm

 

Dense white fumes generate around glass rod

Brown solution

 

NH4+ may be Confirmed 

NH4+  is Confirmed

Result: in given sample of salt on acidic radical chloride (Cl-) and one basic radical ammonium (NH4+) are present.

To study proteins from sample and detect their presence in food sample

Aim: To study proteins from sample and detect their presence in food sample. 

Material required: Test-tube, test-tube stand, test tube holder, glass rod, burner etc.

Theory: Proteins are high molecular mass, long chain polymers composed of a amino acid. Amino acids are molecule that have both -NH2 and –COOH group.

 

S.N.

EXPERIMENT

OBSERVATION

INFERENCE

1.

Biuret test: Sample + NaOH

+ Dil. CuSO4 solution

Bluish violet colour appears

Protein is present

2.

Xanthoprotein test: Sample

+ few drops of conc. HNO3

+ D

Yellow ppt.

Protein is present

3.

Million’s test: Sample + 2 drops of millions reagent +

D

White ppt which changes to brick red on boiling

Protein is present

4.

Ninhydrin test: Protein sample + Few drops of ninhydrin solution + Boil

the contents for 1 minute

Blue colour appear

Protein is present

 

Result: Protein is present in given sample of food.

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