Salt Analysis

SALT ANALYSIS SL NO. EXPERIMENT

OBSERVATION

INFERENCE

PRILIMINARY TEST A. Physical Examination Examination Of Salt 01.

Note the colour of the salt.

Colourless

Shows the absence of Cu-, Ni -, Fe-, Fe-, Mn-, Co-, etc.

02.

Note the odor of the salt.

(i) Ammoniacal smell

NH4- may be present.

(ii) Vinegar like smell

CH3COO- may be present

Soluble

Pb-is absent

Soluble

NH4-, CH3COO- may be present

(i)

Dull-Bluish white

Pb- may be present

(ii)

Green flashes

Zn- or Mn- may be present

03.

Solubility (i) In dil. HCl (ii)

04.

In H2O

Flame Test: Test: - Make a paste of the salt given in a drop of concentrate HCl on a clean watch glass. Dip a glass rod in this paste and heat. Note down the colour imparted by the flame.

(iii) Apple Green

Ba- may be present

(iv) Brick Red

Ca- may be present

(v)

Sr- may be present

Crimson Red ACID RADICALS (Anions)

B. Identification Test Test Of Acid Radicals (Anions)

01.

Dil. H2SO4 Test:  Test: - Take a small quantity of salt in a test tube. Add 1-2 ml of dil. H2SO4. Observe in cold and then gently warm. Note the gas evolved.

(i) A colourless odorless gas with brisk brisk effervesces which turns limewater milky.

Eq:

CO3-+ H2SO4

(ii) Vinegar like smell smell evolved.

Eq:

2CH3COO-+ H2SO4

CO3- may be present

CO2 + SO4-+ H2O CH3COO- may be present

2CH3COOH+ SO4-

02.

Conc. H2SO4 Test: - Take a small quantity of salt with con. H2SO4 (2-3 ml) in a test tube. Identify the gas evolved in cold and then on heating.

Cl- may be present

(i) Colourless gas (HCl) with pungent smell, white fumes with aq. NH4OH.

Eq: Eq: (ii)

Cl-+ H2SO4

HSO4+HCl

HCl+ NH4OH

NH4Cl+ H2O

Reddish brown gas (NO2) with pungent smell, turns

NO3- may be present

FeSO4 solution black

Eq:

NO3-+ H2SO4

Eq:

4HNO3

HSO4-+ HNO3 4NO2+ O2++ 2H20 CH3COO- may be present

(iii) Colourless vapors, vinegar smell, turn blue litmus red.

Eq:

CH3COO-+ H2SO4

HSO4-+ CH3COOH

(iv) A colourless gas, which turns limewater milky, and a gas, which burns with pale-bluish flame.

Eq: (v) 03.

KMnO4 Test: - To a pinch of salt in the test tube add about 2 ml of dil. H2SO4. Boil off any gas evolved. Add little more dil. H 2SO4 and then KMnO4 solution drop wise. Note the changes.

C2O4-+ H2SO4

No gas is evolved.

C2O4- may be present

CO+ CO2+ H2O+ SO4Absence of Cl-, NO3-, C2O4-, etc.

KMnO4 decolorized In cold: (i) With evolution of greenish gas.

Cl- may be present

(ii) With evolution of reddish gas.

Br- may be present

(iii) With evolution of violet gas.

l- may be present

On Warming: (i) With evolution of CO2

C2O4- may be present

KMnO4 is not decolorized

Absence of Cl-, Br-, l-, C2O4-

C. Identification Test Of Independent Radicals (SO4- and PO4-)

01.

To the salt solution add Bacl2

White Precipitate.

SO4- may be present

Eq: 02.

To the above precipitate add dilute HCl

SO4- + BaCl2 

BaSO4 + 2ClSO4- may be present

White precipitate in unchanged. D. Confirmatory Test For Anions

01.

02.

03.

Carbonate (CO3-) (i) Add MgSo4 solution to the salt solution. (ii) To a part of the salt solution add a few drops o f phenolphthalein. Acetate (CH3COO-) (i) Ester Test: Take a pinch of salt in a test tube. Add 1ml of concentrate H2SO4 and 4-5 drops of rectified spirit. Heat it and smell it. (ii) Neutral Ferric Chloride Test: to the salt solution, add a few drops of neutral ferric chloride solution. Filter it. Chloride (Cl-) (i) AgNO3 Test: To a portion of the aqueous solution of the salt, add dilute HNO3 solution. (ii) MnO2 Test: Heat a pinch of the solid salt with MnO2 and concentrate H2SO4

White precipitate It turns pink colour

CO3- is confirmed CO3- is confirmed

Fruity smell.

CH3COO- is confirmed.

Eq:

CH3COO- + C2H5OH-

Nitrate (NO3-) (i) Paper Ball Test: Take a pinch of the salt. Add 1-2 ml of H2SO4. Add a piece of paper ball and heat.

(ii) Brown Ring Test: To the salt solution add, freshly prepared FeSO4 solution. Then add concentrate H2SO4 along the side of test tube drop wise. 05.

Oxalates (C2O42-)

CH3COO- is confirmed.

Deep red colour is produced

Eq:

3CH3COO- + FeCl3

Curdy white precipitate soluble in NH4OH.

Eq:

Cl- + AgNO3

Fe(CH3COO)3 + 3Cl-

Cl- is confirmed.

AgCl + NO3Cl- is confirmed.

Greenish yellow gas evolved.

Eq: Eq:

04.

CH3COOC2H5 + OH-(Ester ,Fruity smell)

Cl- + H2SO4

MnO2 + 4HCl

HCl + HSO4 MnCl2 + 2H2O + Cl2 NO3- confirmed.

Intense brown fumes

Eq:

2NO3- + H2SO4 

Eq: C + 4HNO3 CO2 + Brown ring formed at the junction of two solution.

2HNO3+ SO424NO2(Brown Fumes) + 2H2O NO3- confirmed.

(i) Calcium Chloride Test: To the salt solution add dilute CH3COOH and add CaCl2 solution.

C2O42- confirmed.

White Precipitate

Eq:

COO- + CaCl2

CaC2O4 + 2Cl

COOEq: CaC2O4 + H2SO4

COOH + CaSO4 (White Precipitate) COOH

(ii) KMnO4 Test: Dissolve the above white precipitate in dilute H 2SO4 and add 1 ml of KMnO4 solution.

Pink colour discharged with a steady effervescence.

Eq:

2MnO4- + 5COO- + 16H+

C2O42- confirmed.

2Mn2+ + 10CO3 + 8H2O

COO06.

Sulphates (SO42-) (i) Lead Acetate Test: To a portion of the salt solution, add CH3COOH. Boil off CO2, cool it. Add Pb(CH3COOH)2 solution. (ii) BaCl2 Test: To the salt solution, add few drops of dilute HCl and then BaCl2 solution.

White precipitate soluble in excess of Ammonium Acetate.

SO42- confirmed.

White precipitate insoluble in dilute HCl.

SO42- confirmed.

BASIC RADICALS (Cations) E. Identification Test Of Basic Radicals (Cations) 01. 02. 03. 04. 05. 06. 07. 08. 09.

10. F. Confirmatory Test Of Cations 01. 02. 03. 04. 05. 06.