Analytical Chemistry

Question 1

Colour : Cu 2+

Answer 1

Blue / Green

Question 2

Colour : Cr 3+

Answer 2

Green

Question 3

Colour : Mn 2+

Answer 3

Pink

Question 4

Colour : Fe 2+

Answer 4

Green

Question 5

Colour : Fe 3+

Answer 5

Yellow/Brown

Question 6

Colour : Co 2+

Answer 6

Blue [Pink]

Question 7

Colour : Ni 2+

Answer 7

Green

Question 8

Colour : MnO4 1-

Answer 8

Pink [Purple]

Question 9

Colour : Cr2O7 2-

Answer 9

Orange

Question 10

Calcium Nitrate + Sodium Hydroxide =>

Answer 10

Ca(NO3)2 + 2NaOH => 2NaNO3 + Ca(OH)2

Calcium Hydroxide - Insoluble White Precipitate

Question 11

Calcium Nitrate + Ammonium Hydroxide =>

Answer 11

Concentration of OH -1 is low and cannot form precipitate.

Question 12

Magnesium Chloride + Sodium Hydroxide =>

Answer 12

MgCl2 + 2NaOH => 2NaCl + Mg(OH)2

Magnesium Hydroxide - Insoluble Dull White Precipitate

Question 13

Magnesium Chloride + Ammonium Hydroxide =>

Answer 13

MgCl2 + 2NH4OH => 2NHCl + Mg(OH)2

Magnesium Hydroxide - Insoluble Dull White Precipitate

Question 14

Ferrous Sulphate + Sodium Hydroxide =>

Answer 14

FeSO4 + 2NaOH => Na2SO4 + Fe(OH)2

Ferrous Hydroxide - Insoluble Dirty Green Precipitate

Question 15

Ferrous Sulphate + Ammonium Hydroxide =>

Answer 15

FeSO4 + 2NH4OH => (NH4)2SO4 + Fe(OH)2

Ferrous Hydroxide - Insoluble Dirty Green Precipitate

Question 16

Ferric Chloride + Sodium Hydroxide =>

Answer 16

FeCl3 + 3NaOH => 3NaCl + Fe(OH)3

Ferric Hydroxide - Insoluble Reddish Brown Precipitate

Question 17

Ferric Chloride + Ammonium Hydroxide =>

Answer 17

FeCl3 + 3NH4OH => 3NH4Cl + Fe(OH)3

Ferric Hydroxide - Insoluble Reddish Brown Precipitate

Question 18

Cupric Sulphate + Sodium Hydroxide =>

Answer 18

CuSO4 + 2NaOH => Na2SO4 + Cu(OH)2

Cupric Hydroxide - Insoluble Pale Blue Precipitate

Question 19

Cupric Sulphate + Ammonium Hydroxide =>

Answer 19

CuSO4 + 2NH4OH => (NH42)SO4 + Cu(OH)2

Cupric Hydroxide - Soluble Pale Blue Precipitate

Question 20

Cupric Hydroxide + Ammonium Sulphate + Ammonium Hydroxide[excess] =>

Answer 20

CuSO4 + (NH4)2SO4 + 2NH4OH[excess] => 4H2O + [Cu(NH3)4]SO4

Tetrammine Copper Sulphate - Inky Blue Solution

Question 21

Cupric Hydroxide + Ammonium Hydroxide[excess] =>

Answer 21

Cu(OH)2 + 4NH4OH[excess] => 4H2O + Cu(NH3)42

Tetrammine Copper Hydroxide - Deep Blue Solution

Question 22

Zinc Sulphate + Sodium Hydroxide =>

Answer 22

ZnSO4 + 2NaOH => Na2SO4 + Zn(OH)2

Zinc Hydroxide - Soluble Gelatinous White Precipitate

Question 23

Zinc Hydroxide + Sodium Hydroxide[excess] =>

Answer 23

Zn(OH)2 + 2NaOH[excess]=> 2H2O + Na2ZnO2

Sodium Zincate - Colorless Solution

Question 24

Zinc Hydroxide + Ammonium Sulphate + Ammonium Hydroxide[excess] =>

Answer 24

ZnSO4 + (NH4)2SO4 + 2NH4OH[excess] => 4H2O + [Zn(NH3)4]SO4

Tetrammine Zinc Sulphate - Colorless Solution

Question 25

Zinc Hydroxide + Ammonium Hydroxide[excess] =>

Answer 25

Zn(OH)2 + 4NH4OH[excess] => 4H2O + Zn(NH3)42

Tetrammine Zinc Hydroxide - Colorless Solution

Question 26

Plumbous Nitrate + Sodium Hydroxide =>

Answer 26

Pb(NO3)2 + 2NaOH => 2NaNO3 + Pb(OH)2

Plumbous Hydroxide - Soluble Chalky White Precipitate

Question 27

Plumbous Hydroxide + Sodium Hydroxide[excess] =>

Answer 27

Pb(OH)2 + 2NaOH[excess] => 2H2O + Na2PbO2

Sodium Plumbite - Colorless Solution

Question 28

Plumbous Nitrate + Ammonium Hydroxide =>

Answer 28

Pb(NO3)2 + 2NH4OH => 2NH4NO3 + Pb(OH)2

Plumbous Hydroxide - Insoluble Chalky White Precipitate

Question 29

Zn, Pb + 2KOH , 2NaOH [hot & conc.]

Answer 29

Sodium/Potassium Zincate/Plumbite + H2

Question 30

2Al + 2H2O + 2NaOH/2KOH [hot & conc.]

Answer 30

2NaAlO2 / 2KAlO2 + 3H2

Question 31

Amphoteric Oxide/Hydroxide + Alkali [hot & conc.]

Answer 31

Respective Metal Zincate/ Plumbite/Aluminate + Water