Qualitative Analysis + Reactions of metals

Question 1

Colours of metals (those in the reactivity series)

Answer 1

K & Na: Dull grey solid
Ca - Pb: Silvery grey solid
Cu: Reddish brown
Hg: Silver liquid
Ag: Shiny silver liquid
Au: Shiny gold liquid
Pt: Shiny silver solid

Question 2

Reactivity of metals with water

Answer 2

K - Ca: React with cold water –> Alkali + hydrogen
Mg - Pb: React with steam –> Metal oxide + hydrogen
Cu onwards: No reaction

Question 3

Reactivity of metals with oxygen

Answer 3

K - Hg: React with oxygen –> Metal oxide

Below Hg: No reaction

Question 4

Colours of group I, II & III, and ammonium compounds

Answer 4

White solid

Question 5

Colour of zinc oxide

Answer 5

Yellow when hot, white when cold

Question 6

Reactivity of metals with dilute acids

Answer 6

K - Pb: React –> Salt + hydrogen

Question 7

Colour of iron(II) oxide

Answer 7

Black

Question 8

Colour of iron (III) oxide

Answer 8

Reddish brown

Question 9

Colour of copper(II) oxide

Answer 9

Black

Question 10

Colour of copper(I) oxide

Answer 10

Reddish brown

Question 11

Colour of copper(II) carbonate

Answer 11

Green

Question 12

Colour of copper(II) sulfate

Answer 12

Blue

Question 13

Colour of copper(II) chloride solution

Answer 13

Bluish green

Question 14

Colour of copper(II) hydroxide (insoluble)

Answer 14

Blue

Question 15

Colour of zinc hydroxide (insoluble)

Answer 15

White

Question 16

Colour of iron(II) hydroxide (insoluble)

Answer 16

Dirty green

Question 17

Colour of iron(III) hydroxide (insoluble)

Answer 17

Reddish brown

Question 18

Colour & state of carbon

Answer 18

Black solid

Question 19

Colour & state of fluorine at rtp

Answer 19

Pale yellow gas

Question 20

Colour & state of bromine at rtp

Answer 20

Reddish brown liquid

Question 21

Colour of iodine (all states)

Answer 21

Black solid, yellow-brown liquid, violet vapour

Question 22

Change in colour of potassium manganate(VII) KMnO4`

Answer 22

When reduced, turns from purple –> colourless

Question 23

Change in colour of potassium dichromate(VI) K2Cr2O7`

Answer 23

When reduced, turns from orange –> green

Question 24

Black oxides

Answer 24

Copper(II) oxide, Iron(II) oxide, Manganese(IV) oxide

Question 25

Identification of aluminium ion

Answer 25

NaOH White precipitate Al(OH)3 formed Dissolves in excess NaOH NH3 White precipitate Al(OH)3 formed Insoluble in excess NH3

Question 26

Identification of lead(II) ion

Answer 26

NaOH White precipitate Pb(OH)2 formed Dissolves in excess NaOH NH3 White precipitate Pb(OH)2 formed Insoluble in excess NH3

Question 27

Identification of zinc ion

Answer 27

NaOH White precipitate Zn(OH)2 formed Dissolves in excess NaOH NH3 White precipitate ZN(OH)2 formed Dissolves in excess NH3

Question 28

Identification of calcium ion

Answer 28

NaOH White precipitate Ca(OH)2 formed Insoluble in excess NaOH NH3 No precipitate

Question 29

Identification of copper(II) ion

Answer 29

NaOH Blue precipitate Cu(OH)2 formed Insoluble in excess NaOH NH3 Blue precipitate Cu(OH)2 formed Dissolves in excess NH3 to give dark blue solution

Question 30

Identification of iron(II) ion

Answer 30

NaOH Dirty green precipitate Fe(OH)2 formed Insoluble in excess NaOH NH3 Dirty green precipitate Fe(OH)2 formed Insoluble in excess NH3

Question 31

Identification of iron(III) ion

Answer 31

NaOH Reddish brown precipitate Fe(OH)3 formed Insoluble in excess NaOH NH3 Reddish brown precipitate Fe(OH)3 formed Insoluble in excess NH3

Question 32

Identification of ammonium ion

Answer 32

NaOH No precipitate Pungent ammonia gas evolved on heating NH3 No reaction

Question 33

Identification of halide ions

Answer 33

Add dilute nitric acid + aqueous silver nitrate Chlorine: White precipitate AgCl Iodine: Yellow precipitate AgI

Question 34

Identification of carbonate ion

Answer 34

Add dilute hydrochloric acid | Carbon dioxide gas produced

Question 35

Identification of nitrate ion

Answer 35

Add aqueous sodium hydroxide + a small amount of aluminium powder + warm the mixture Pungent ammonia gas produced

Question 36

Identification of sulfate ion

Answer 36

Add dilute nitric acid + barium nitrate | White precipitate BaSO4 formed

Question 37

Identification of hydrogen

Answer 37

Extinguishes lighted splint with a 'pop' sound

Question 38

Identification of oxygen

Answer 38

Rekindles glowing splint

Question 39

Identification of carbon dioxide

Answer 39

Forms a white precipitate with limewater Ca(OH)2 | Precipitate: CaCO3

Question 40

Identification of ammonia

Answer 40

Turns damp red litmus paper blue | Pungent smell

Question 41

Identification of chlorine

Answer 41

Turns damp blue litmus paper red | Greenish yellow gas, choking smell

Question 42

Identification of nitrogen dioxide gas

Answer 42

Reddish brown in colour, pungent

Question 43

Identification of sulfur dioxide gas

Answer 43

Smell of burnt matches