Unit 3

Question 1

Colour of [Cu(H₂O)₆]²⁺

Answer 1

Pale blue

Question 2

Colour of [Fe(H₂O)₆]²⁺

Answer 2

Pale green

Question 3

Colour of [Fe(H₂O)₆]³⁺

Answer 3

Yellow

Question 4

Colour of [Cr(H₂O)₆]³⁺

Answer 4

Indigo

Question 5

Colour of Zn²⁺

Answer 5

Colourless

Question 6

Colour of Cu(H₂O)₄(OH)₂

Answer 6

Sky blue precipitate

Question 7

Colour of Fe(H₂O)₄(OH)₂

Answer 7

Dark green

Question 8

Colour of Fe(H₂O)₃(OH)₃

Answer 8

Rust brown

Question 9

Colour of Cr(H₂O)₃(OH)₃

Answer 9

Grey-green precipitate

Question 10

Colour of Zn(OH)₂

Answer 10

White precipitate

Question 11

Equations for amphoteric nature of Aluminium Oxide

Answer 11

Al₂O₃ + 6HCl → 2AlCl₃ + 3H₂O

Al₂O₃ + 2NaOH + 3H₂O → 2Na[Al(OH)₄]₍ₛ₎

Question 12

Equations for amphoteric nature of Aluminium Hydroxide

Answer 12

Al(OH)₃ + 3HCl → AlCl₃ + 3H₂O

Al(OH)₃ + NaOH → Na[Al(OH)₄]₍ₛ₎

Question 13

Equations for amphoteric nature of Lead Oxide

Answer 13

PbO + 2HNO₃ → Pb(NO₃)₂ + H₂O

PbO + 2NaOH + H₂O → Na₂[Pb(OH)₄]₍ₛ₎

Question 14

Equations for amphoteric nature of Lead Hydroxide

Answer 14

Pb(OH)₂ + 2HNO₃ → Pb(NO₃)₂ + 2H₂O

Pb(OH)₂ + 2NaOH → Na₂[Pb(OH)₄]₍ₛ₎

Question 15

Hexagonal Boron Nitride

Answer 15

Hexagonal sheets lie directly above each other
Weak forces between layers
No delocalised electrons (is an insulator)
Polar

Question 16

Cubic Boron Nitride

Answer 16

Tetrahedral - very hard, high melting point
Used for water resistant coating and industrial abrasives

Question 17

SiCl₄ and CCl₄ appearance at room temperature

Answer 17

Both colourless liquids

Question 18

Lead (IV) Chloride at room temperature reaction

Answer 18

PbCl₄ → PbCl₂₍ₛ₎ + Cl₂

Question 19

CCl₄ reaction with water

Answer 19

No reaction

Question 20

SiCl₄ reaction with water

Answer 20

Steamy fumes (HCl₍₉₎), white precipiate (SiO₂₍ₛ₎)

SiCl₄₍ₗ₎ + 2H₂O₍ₗ₎ → SiO₂₍ₛ₎ + 4HCl₍₉₎

Question 21

PbCl₄ reaction with water

Answer 21

Insoluble in cold water, white solid

Question 22

Chloride and Concentrated Sulfuric Acid

Answer 22

NaCl₍ₛ₎ + H₂SO₄₍ₗ₎ → NaHSO₄₍ₛ₎ + HCl₍₉₎

White steamy fumes (HCl₍₉₎)

Question 23

Bromide and Concentrated Sulfuric Acid

Answer 23

NaBr₍ₛ₎ + H₂SO₄₍ₗ₎ → BrHSO₄₍ₛ₎ + HBr₍₉₎
2HBr₍₉₎ + H₂SO₄₍ₗ₎ → Br₂₍₉₎ + SO₂₍₉₎ + 2H₂O₍ₗ₎

White steamy fumes (HBr₍₉₎), Orange fumes (Br₂₍₉₎)

Question 24

Iodide and Concentrated Sulfuric Acid

Answer 24

NaI₍ₛ₎ + H₂SO₄₍ₗ₎ → NaHSO₄₍ₛ₎ + HI₍₉₎
2HI₍₉₎ + H₂SO₄₍ₗ₎ → I₂₍₉₎ + SO₂₍₉₎ + 2H₂O₍ₗ₎
6HI₍₉₎ + H₂SO₄₍ₗ₎ → 3I₂₍₉₎ + S₍ₛ₎ + 4H₂O₍ₗ₎
8HI₍₉₎ + H₂SO₄₍ₗ₎ → 4I₂₍₉₎ + H₂S₍₉₎ + 4H₂O₍ₗ₎

White steamy fumes (HI₍₉₎), Purple fumes (I₂₍₉₎), Yellow solid (S₍ₛ₎), Rotten egg smell (H₂S₍₉₎)