GCSE - test for ions

Question 1

Test for sulphate ions

Answer 1

Bacl2
Pos - formes a white ppt

Question 2

Test for hydroxide ions

Answer 2

Test if alkaline
Pos - red litmus to blue

Question 3

Test for carbonate ions

Answer 3

Hcl
Pos - Effifecents of co2 / turns cloudy

Question 4

Test for group 2 ions

Answer 4

Flame test
Ca (II) - brick red
Sr (II) - red
Ba (II) - pale green

Question 5

Test for ammonia ions

Answer 5

Ammonia released
So use red litmus paper or add naoh
Pos - Red paper to blue paper

Question 6

Test fro metal hydroxides

Answer 6

Naoh is added
Pos - formes a ppt

Question 7

test for group 2 ions (3 test)

Answer 7

Ammonium solution
mg ions - white ppt (mg(OH)2)
ca ions - no change observed
sr ions - no change observed
Ba - no change observed

Excess NaOH
mg ions - whute ppt
ca ions - white ppt of the hydroxide
sr ions - slightley white ppt of the hxdroxide
ba ions - no change oberved

excess sulfuric acid
mg ions - colourless solution
ca ions - slightly white ppt CaSO4
sr ions - white ppt - SrSO4
ba ions - BaSO4

Question 8

test for hysroxide ions ad halide ions

Answer 8

halode ions - nitric acid, silver nitrate cl- white , br - cream, i- yellow
to double tes - add dilute ammon, cl- disolves, br - disolves if conc, i - just doesnt

hydroxide ions - red litmus paper - turns blue

sample must be aq to test

Question 9

test for ammonia ions

Answer 9

warm with NaOH
test fumes produced with red litmus paper - changes to blue in presence of ammonia gas
NH4+ (aq) + OH- (aq) → NH3 (g) + H2O (l)

Question 10

test for carbonate ions

Answer 10

small amount (around 1 cm3) of dilute hydrochloric acid should be added to a test tube
An equal amount of sodium carbonate solution should then be added to the test tube
As soon as the sodium carbonate solution is added, a bung with a delivery tube should be attached to the test tube
The delivery tube should transfer the gas which is formed into a different test tube which contains a small amount of limewater (calcium hydroxide solution)

Carbonate ions will react with hydrogen ions from the acid to produce carbon dioxide gas
Carbon dioxide gas will turn the limewater milky

Question 11

test for sulphate ions

Answer 11

sulphate ions SO4 2- add barium chloride - white ppt firmed of BaSO4
Ba2+ (aq) + SO42- (aq) → BaSO4 (s)