Chemistry Practicals | Premium Lab Guide

EXPERIMENT - 3

Salt Analysis

Aim: To analyse the given inorganic salt for acidic and basic radicals [(NH₄)₂CO₃]

Preliminary Investigation

Physical State: Solid
Colour: White (Cu²⁺, Fe²⁺, Fe³⁺, Ni²⁺, Mn²⁺, Co²⁺ absent)
Odour: Ammonium smell (may be NH₄⁺)
Solubility: Soluble in water
Flame Test: No Characteristic flame (Pb²⁺, Cu²⁺, Ca²⁺ Sr²⁺, Ba²⁺, Zn²⁺ absent)

(A) Identification of Acidic Radical

(a) Preliminary test:

Experiment	Observation	Inference
1. Salt solution + dil H₂SO₄	Colourless, colourless gas with brisk effervescence which turn lime water milky	Group A anion (CO₃^2- may be present)

Confirmative test:

Experiment	Observation	Inference
1. BaCl₂ Test: Salt solution + BaCl₂	White ppt of BaCO₃	CO₃^2- Confirmed
2. MgSO₄ Test: Salt solution + MgSO₄	White ppt of MgCO₃	CO₃^2- Confirmed

(B) Identification of Basic Radical

(a) Preliminary Test:

Experiment	Observation	Inference
1. Salt Solution + NaOH + Heat	Smell of NH₃	Zero group present (NH₄⁺ may be)
2. Place a red litmus on the mouth of test tube.	Red litmus turns blue

Confirmative test:

Experiment	Observation	Inference
1. Nessler's reagent test: Salt + Solution + NaOH + Nessler's Reagent	Reddish brown ppt. is formed	NH₄⁺ confirmed.
2. NaOH test: Salt Solution + NaOH + Heat. Bring a glass rod dipped in conc. HCl	Smell of NH₃. Dense white fumes of NH₄Cl are formed.	NH₄⁺ Confirmed.

Chemical Reactions

Acidic Radical

Preliminary Test:

(NH₄)₂CO₃ + H₂SO₄ → (NH₄)₂SO₄ + CO₂↑ + H₂O
Ca(OH)₂ + CO₂ → CaCO₃ + H₂O

Confirmative Test:

BaCl₂ Test: (NH₄)₂CO₃ + BaCl₂ → BaCO₃↓ + 2NH₄Cl
MgSO₄: (NH₄)₂CO₃ + MgSO₄ → MgCO₃↓ + (NH₄)₂SO₄

Basic Radical

(a) Preliminary Test:

(NH₄)₂CO₃ + 2NaOH → Na₂CO₃ + 2H₂O + 2NH₃↑
NH₃ + Red litmus → Litmus turns blue

(b) Confirmative test:

Nessler's Test: K₂HgI₄ → 2KI + HgI₂
HgI₂ + NH₃ → NH₂HgI + HI
2NH₂HgI + H₂O → NH₂HgO + NH₄I
NaOH Test:
(NH₄)₂CO₃ + 2NaOH → Na₂CO₃ + 2H₂O + 2NH₃↑
NH₃↑ + HCl → NH₄Cl (Dense white fumes)

Result

The given inorganic salt contains following:

Acidic Radical: CO₃^2-
Basic Radical: NH₄⁺

EXPERIMENT - 4

Salt Analysis

Aim: To analyse the given salt of acidic and basic radical (NH₄Cl)

Preliminary Investigation

Physical state: Solid
Colour: white (Cu²⁺, Fe²⁺, Fe³⁺, Ni²⁺, Mn²⁺, Co²⁺ absent)
Odour: Ammonium smell (NH₄⁺ may be present)
Solubility: Soluble in water
Flame Test: No characteristic flame (Cu²⁺, Ca²⁺, Ba²⁺, Sr²⁺, Pb⁺², Zn²⁺ absent)

(A) Identification of Acidic Radical

a- Preliminary test:

Experiment	Observation	Inference
1. Salt solution + dil H₂SO₄ solution	No gas is evolved	Group A anion absent
2. Salt + Conc H₂SO₄ + Heat. Bring a glass rod dipped in NH₄OH	Colourless gas with pungent smell which gives dense white fumes of NH₄Cl	Group B anion (Cl may be)

(b) Confirmative Test:

Experiment	Observation	Inference
1. AgNO₃ test: Salt Solution + AgNO₃. Dissolve the ppt in NH₄OH	Curdy white ppt. White ppt soluble in NH₄OH	Cl confirmed
2. Chromyl chloride Test: a) Salt + Solid K₂Cr₂O₇ (1:2) + conc. H₂SO₄ + Heat b) Pass these vapour through NaOH c) Add acetic acid and lead acetate to yellow solution	Reddish orange gas is evolved. Solution becomes yellow. Yellow ppt of lead chromate is formed.	Cl confirmed

Identification of Basic Radical

Preliminary Test:

Experiment	Observation	Inference
1. Salt solution + NaOH + Heat	Smell of Ammonia	Zero group (NH₄⁺) May be
2. Place a red litmus on the mouth of test tube	Red litmus turns blue

Confirmative Test:

Experiment	Observation	Inference
1. Nessler Test: Salt solution + NaOH + Nessler's reagent	Reddish brown ppt is formed	NH₄⁺ Confirmed
2. NaOH Test: Salt Solution + NaOH + Heat. Bring a glass rod dipped in dil HCl	Smell of NH₃. white dense fumes of NH₄Cl are formed	NH₄⁺ Confirmed

Result

The given inorganic salt contains:

Acidic Radical: Cl^-
Basic Radical: NH₄⁺

EXPERIMENT - 5

Salt Analysis

Aim: To analyze the given inorganic salt for acidic and basic radical. Pb(NO₃)₂

Preliminary Investigation

Physical state: Solid
Colour: Creamish white (Cu²⁺, Co²⁺, Ni^{2+}, Fe²⁺, Mn²⁺}, Fe³ absent)
Odour: No characteristic odour (NH₄⁺, S^2-, CH₃COO^- absent)
Solubility: Soluble in water
Flame Test: Dull Bluish white flame is obtained (Pb²⁺ may be)

(A) Identification of Acidic Radical

a- Preliminary test:

Experiment	Observation	Inference
1. Salt solution + dil H₂SO₄ solution	No gas is evolved	Group A absent
2. Salt + Conc H₂SO₄ + Heat	Brown Coloured gas (NO₂) is evolved	Group B (NO₃^- may be present)

(b) Confirmative test:

Experiment	Observation	Inference
1. Diphenyl amine test : salt + Conc H₂SO₄ + diphenyl amine	Deep blue coloured solution	NO₃^- confirmed
2. Ring Test: Salt + Freshly prepared FeSO₄ + Conc H₂SO₄ along the side of the test tube	Brown ring is formed at the junction of two liquids	NO₃^- confirmed

Identification of Basic Radical

a- Preliminary test:

Experiment	Observation	Inference
1. Salt solution + NaOH	No Smell of ammonia	Zero group [NH₄⁺] absent
2. Salt Solution + dil HCl. Filter the above ppt and boil it with water and divide into parts.	White ppt of PbCl₂ is formed	I group [Pb²⁺ may be]

a- Confirmative test:

Experiment	Observation	Inference
1. KI test: 1st part + KI	PbI₂ (Yellow Ppt)	Pb²⁺ Confirmed
2. K₂CrO₄ Test: 2nd part + K₂CrO₄	Yellow ppt of PbCrO₄ is formed	Pb²⁺ Confirmed

Result

The given inorganic salt contains:

Acidic Radical: NO₃^-
Basic Radical: Pb⁺²

EXPERIMENT - 7

Salt Analysis

Aim: To analyze the given inorganic salt for acidic and basic radical. Al₂(SO₄)₃

Preliminary Investigation

Physical state: Solid
Colour: White
Odour: No characteristic odour
Solubility: Soluble in water.
Flame Test: No characteristics flame

(A) Identification of Acidic Radical

a- Preliminary test:

Experiment	Observation	Inference
1. Salt solution + dil H₂SO₄	No gas is evolved	Group A Absent
2. Salt + Conc H₂SO₄ + Heat	No gas evolved	Group B anions absent
3. Salt + BaCl₂	White ppt is formed	Group C anion SO₄^2- may be

(b) Confirmative test:

Experiment	Observation	Inference
1. BaCl₂ test: Salt Solution + BaCl₂. Add dil HCl to above ppt	White Ppt. Ppt remains insoluble	SO₄^2- confirmed
2. Lead Acetate Test: Salt Solution + (CH₃COO)₂Pb solution. Add CH₃COONH₄ to above ppt.	White ppt. Ppt dissolves in ammonium acetate.	SO₄^2- confirmed

B- Identification of Basic Radical

(a) Preliminary test:

Experiment	Observation	Inference
1. Salt solution + NaOH + heat	No smell of NH₃	Zero Group absent
2. Salt solution + dil. HCl	No Ppt	Group I absent
3. To the above solution pass H₂S gas	No ppt.	Group II absent
4. Boil H₂S gas and add NH₄Cl + NH₄OH & divide the Solution in two parts.	White gelatinous ppt.	Group III (Al³⁺ may be)

(b) Confirmative test:

Experiment	Observation	Inference
1. Lake test: 1st part + dil HCl + 2 drops of blue litmus + NH₄OH	Blue ppt floats over colourless solution	Al³⁺ confirmed
2. Ammonium chloride Test: IInd part + NH₄Cl + Boil the solution	Formation of white gelatinous ppt.	Al³⁺ confirmed

Result

The given inorganic salt contains:

Acidic Radical: SO₄^2-
Basic Radical: Al⁺³

EXPERIMENT - 12

Titration Prep

Aim: To prepare 250 ml of 0.02 M (M/50) Mohr's Salt solution.

Apparatus Required

Chemical balance, weight box, beaker (250 ml), watch glass, volumetric flask (250 ml) glass rod, funnel, test tube.

Chemical Required

Mohr's salt, conc. H₂SO₄, Distilled water.

Theory

Molecular formula of Mohr's salt - FeSO₄(NH₄)₂SO₄.6H₂O
It is primary standard, hence its solution can be prepared by direct weighing.
Molecular weight of Mohr's salt: 392 g.
Thus to prepare 1000 ml of 1M Mohr's salt solution, 392 g of Mohr's salt is needed. To prepare 250ml of 1 M Mohr's salt 392/1000 × 250 ie 392/4 g of mohr's salt is need.
To prepare 250 ml of 0.02 of Mohr's salt solution (392/4 × 0.02)g of salt is needed. Mohr's salt required = 1.9600 g of mohr's salt.

Observation

1. Weight of empty watch glass (W1) = 21.7200 g
2. Weight of empty watch glass + mohr's salt (W2) = 21.7200 + 1.9600 = 23.6800 g
3. Weight of Mohr's Salt [W2 - W1] = 23.6800 - 21.7200 = 1.9600 g
4. Volume of solution = 250 ml
5. Morality of solution = M/50

Precautions

1. Add 2-3 ml of conc. H₂SO₄ to prevent hydrolysis of FeSO₄ before making solution of 250 ml.
2. Weighing should be done accurately.
3. Apparatus should be clean.

Result

250 ml of M/50 solution of Mohr's salt is prepared.

EXPERIMENT - 13

Titration

Aim: To prepare a standard solution of M/50 Mohr's salt solution. With its help, determine molarity and strength of KMnO₄ Solution.

Theory

(a) Preparation of standard or known solution of M/50 Mohr's salt solution: Mohr's salt is a primary standard solution. Hence its can be prepared by direct weighting.
Molecular weight of mohr's salt: 392 g/mol. To prepare 250 ml of 0.02 of Mohr's salt solution, Mohr's salt required = 1.9600 g.

(b) Titration of Mohr's salt Sol: (standard solution) with KMnO₄ (unknown solution). KMnO₄ is strong and versatile oxidizing agent. When its treated with Mohr's salt solution in sufficiently acidic medium Fe²⁺ ion are oxidised to Fe³⁺.

Observations

1. Preparation of standard solution:

Weight of empty water glass (W1): 21.7200 g
Weight of watch glass + Mohr's salt (W2): 23.6800 g
Weight of Mohr's salt = W2 - W1: 1.9600 g
Volume of mohr's salt taken for each titration (V2): 20 ml

2. Titration of standard solution with KMnO₄ Solution:

Concordant Reading: 14.6 ml

Calculation

M1V1 = 1/5 M2V2

M1 × 14.6 = 1/5 × M/50 × 20

M1 = 0.0068 M

Strength = 158 × 0.0068 M = 1.0744 g/l

Result

1. Molarity of the given solution = 0.0068 M
2. Strength of the given solution = 1.0744 g/l

EXPERIMENT - 17

Functional Group

Aim: To identify the functional group in the given organic compound.

Physical Properties

State: Solid
Colour: White
Odour: Vinegar Like
Flammability: Burn with non sooty flame (Aliphatic)

Preliminary test:

Experiment	Observation	Inference
1. Litmus test: Organic compound + 2 drops of litmus solution.	Litmus solution turns from blue to red.	-COOH or -OH may be present
2. Organic compound + NaHCO₃ solution.	Colourless, odorless gas with brisk effervescence.	-COOH group may be or -OH (phenol) group present.

Confirmatory test:

Experiment	Observation	Inference
1. Ester test: Organic compound + C₂H₅OH + conc. H₂SO₄ + Heat	Fruity smell of ester	-COOH grp confirmed.
2. FeCl₃ Test: Organic compound + dil FeCl₃ solution.	Red colour appear	-COOH grp confirmed.

Result

The functional group present in the given organic compound is carboxylic acid (-COOH).

EXPERIMENT - 18

Functional Group

Aim: To identify the functional group in the given organic compound.

Physical Properties

State: Liquid
Colour: Colourless
Odour: Spirit Like
Water Solubility: Soluble in Water
Flammability: Burn with non-sooty flame (Aliphatic)

Preliminary test:

Experiment	Observation	Inference
1. Organic compound + blue litmus solution.	No change	-COOH or -OH(Phenol) group absent
2. Organic compound + dil HCl + NaOH	No ppt. or oily layer	NH2 grp. Absent
3. Organic comp + Na metal	H₂ gas evolved	-OH (alcohol) Group may be

Confirmatory test:

Experiment	Observation	Inference
1. Cerric ammonium nitrate Test: Organic compound + cerric ammonium nitrate	Red colour	-OH group confirmed
2. Ester Test: Organic compound + CH₃COOH + Conc. H₂SO₄ + Heat.	Fruity smell of ester.	-OH grp. confirmed

Result

The functional group present in organic compound is alcohol group (-OH).

EXPERIMENT - 19

Functional Group

Aim: To identify the functional group in the given organic compound.

Physical Properties

State: Solid
Colour: White
Odour: Phenolic Smell
Water Solubility: Water insoluble
Flammability: Burn with non-sooty flame (Aromatic)

Preliminary test:

Experiment	Observation	Inference
1. Organic compound + blue litmus solution.	Blue litmus turn Red	-COOH or phenolic (-OH) may be
2. NaHCO₃ test: Organic compound + NaHCO₃ solution.	No effervescence	-COOH absent, Phenolic group may be

Confirmatory test:

Experiment	Observation	Inference
1. FeCl₃ Test: Organic compound + FeCl₃	Green blue or violet colouration	Phenolic (-OH) group confirmed
2. Phthalic test: Organic compound + pthalic acid + 2-3 drops H₂SO₄ + Δ then cool and dil. NaOH	Intense green, blue or red colouration	Phenol (-OH) grp confirmed

Result

The given organic comp. contains phenolic (-OH) grp.

EXPERIMENT - 20

Functional Group

Aim: To identify the functional group in present in the given organic compound.

Physical Properties

State: Liquid
Colour: Colourless
Odour: Pungent
Water Solubility: Soluble in Water
Flammability: Burn with non-sooty flame (Aliphatic)

Preliminary test:

Experiment	Observation	Inference
1. Organic compound + blue litmus solution.	No change	-COOH or phenolic group absent
2. Organic compound + NaOH + dil HCl	No ppt or oily layer	NH₂ grp. Absent
3. Organic comp + 2 ml of 2, 4 DNP shake & allow it to stand.	Orange - red ppt.	-CHO or ketonic group present.

Confirmatory test:

Experiment	Observation	Inference
1. Schiff's solution test: Organic compound + 2 ml of Schiff's reagent.	Pink colour Obtained	-CHO group present
2. Fehling's solution test: Organic compound + Fehling's solution (A+B) + boil in a water bath	Red ppt.	-CHO grp present.

Result

Given organic compound contains aldehydic grp. (-CHO).