Topic 4: Inorganic Analysis

Question 1

Test for Cl, Br or I- ions

Answer 1

Add aqueous silver nitrate (AgNO3)
Followed by dilute nitric acid
Cl - white ppt
Br - cream ppt
I - yellow ppt

Question 2

Confirmatory test for G7 ions

Answer 2

Addition of ammonia
Cl is soluble in dilute
Br is soluble in conc.
I is insoluble in conc.

Question 3

Test for sulphate ions?

Answer 3

Addition of aqueous Barium chloride (BaCl)
Followed by dilute HCl
Forms white ppt of barium sulphate

Question 4

Test for carbonate ions?

Answer 4

Add dilute acid (HCl, H2SO4)
Effervescence and colourless gas produced (CO2 gas)

Question 5

Test for sulphite ions?

Answer 5

Add dilute acid (HCl, H2SO4)
Pungent gas produced, this causes a colour change of acidified potassium dichromate solution from orange –> green

Question 6

Test for ammonium ions?

Answer 6

Add aqueous sodium hydroxide (NaOH) and warm
Gas turns damp red litmus paper blue (smells)

Question 7

Test for group 2 metal ions?

Answer 7

Add aqueous NaOH to solution of compound.
Insoluble white ppt formed

Question 8

Test for nitrate ions?

Answer 8

Warm the solid with aqueous NaOH and add aluminium/zinc powder
Gas turns damp red litmus paper blue
(the gas is ammonia, the ions are reduced to NH3)

Question 9

Flame test for lithium

Answer 9

crimson

Question 10

Flame test for sodium

Answer 10

yellow

Question 11

Flame test for potassium

Answer 11

lilac

Question 12

Flame test for magnesium

Answer 12

no colour

Question 13

Flame test for beryllium

Answer 13

no colour

Question 14

Flame test for calcium

Answer 14

brick red

Question 15

Flame test for barium

Answer 15

green

Question 16

Flame test for strontium

Answer 16

red