QA

Question 1

Ca²⁺ + NaOH

Ionic equation + observations

Answer 1

Ca²⁺ (aq) + 2OH^- (aq) → Ca(OH)₂ (s)
white ppt, insoluble in excess

Question 2

Zn²⁺ + NaOH

Ionic equations + observations

Answer 2

Zn²⁺ (aq) + 2OH^- (aq) → Zn(OH)₂ (s)
white ppt, soluble in excess
Zn(OH)₂ (s) + 2OH^- (aq) → [Zn(OH)₄]^2- (aq)
colourless zincate solution

Question 3

Al³⁺ + NaOH

Ionic equations + observations

Answer 3

Al³⁺ (aq) + 3OH^- (aq) → Al(OH)₃ (s)
white ppt, soluble in excess
Al(OH)₃ (s) + OH^- (aq) → [Al(OH)₄]^- (aq)
colourless aluminate solution

Question 4

Pb²⁺ + NaOH

Ionic equations + observations

Answer 4

Pb²⁺ (aq) + 2OH^- (aq) → Pb(OH)₂ (s)
white ppt, soluble in excess
Pb(OH)₂ (s) + 2OH^- (aq) → [Pb(OH)₄]^2- (aq)
colourless plumbate solution

Question 5

Fe²⁺ + NaOH

Ionic equation + observations

Answer 5

Fe²⁺ (aq) + 2OH^- (aq) → Fe(OH)₂ (s)
dirty green ppt, turns reddish brown Fe(OH)₃ on standing in air

Question 6

Fe³⁺ + NaOH

Ionic equation + observations

Answer 6

Fe³⁺ (aq) + 3OH^- (aq) → Fe(OH)₃ (s)
reddish brown ppt, insoluble in excess

Question 7

Cu²⁺ + NaOH

Ionic equation + observations

Answer 7

Cu²⁺ (aq) + 2OH^- (aq) → Cu(OH)₂ (s)
blue ppt, insoluble in excess

Question 8

Carbonate test

Ionic equation + procedure + observations

Answer 8

Ionic equation: 2H⁺ (aq) + CO₃^2- (aq) → CO₂ (g) + H₂O (l)
Procedure: Add dilute acid
Observation: Effervescence, colourless, odourless gas CO₂ liberated forms white ppt in limewater

Question 9

Sulphate test

Ionic equation + procedure + observations

Answer 9

Ionic equation: Ba²⁺ (aq) + SO₄^2- (aq) → BaSO₄ (s)
Procedure: Add dilute nitric acid HNO₃ / hydrochloric acid HCl then aqueous barium nitrate Ba(NO₃)₂ / barium chloride BaCl₂
Observation: White ppt formed on adding aqueous barium nitrate Ba(NO₃)₂ / barium chloride BaCl₂
(Carbonate present if carbonate test observation observed on adding dilute acid)

Question 10

Chloride / Iodine test

Ionic equations + procedure + observations

Answer 10

Ionic equations:
Ag⁺ (aq) + Cl^- (aq) → AgCl (s)
Ag⁺ (aq) + I^- (aq) → AgI (s)
Procedure: Add dilute nitric acid HNO₃ then aqueous silver nitrate AgNO₃
Observation: White (Cl^-) / yellow (I^-) ppt formed on adding aqueous silver nitrate AgNO₃
(Carbonate present if carbonate test observation observed on adding dilute acid)

Question 11

Heat metal hydroxide

Products

Answer 11

Metal oxide + water

Question 12

Heat metal carbonate

Products

Answer 12

Metal oxide + carbon dioxide

Question 13

Heat metal nitrate

Products

Answer 13

Metal oxide + oxygen + nitrogen dioxide