AQA A-Level Chemistry Chemical Tests – Complete Solutions & Exam Q&A

AQA A-LEVEL CHEMISTRY CHEMICAL
TESTS EXAM QUESTIONS WITH
COMPLETE SOLUTIONS.


Aluminium (Al 3+ ) test - correct answer - add aqueous
sodium hydroxide gives white precipitate which dissolves
in excess


Bromide (Br - ) test - correct answer - add dilute nitric
acid then aqueous silver nitrate. Gives cream precipitate.
Dissolves in concentrated ammonia but not in dilute
ammonia


Calcium (Ca 2+ ) test - correct answer - add aqueous
sodium hydroxide gives white precipitate, insoluble in
excess.


Carbonate (CO 3 2- ) test - correct answer - add dilute
acid; effervescence, carbon dioxide produced


Chloride (Cl - ) test - correct answer - add dilute nitric
acid then aqueous silver nitrate. Gives white precipitate.
Dissolves in dilute ammonia to give colourless solution (of
[Ag(NH 3 ) 2 ] + )

, Chlorine (Cl2 ) test - correct answer - bleaches damp
litmus paper (Cl2 reacts with water to form HCl and HOCl)


Copper (Cu 2+ ) test - correct answer - add aqueous
sodium hydroxide gives blue precipitate, insoluble in
excess. Or add ammonia: gives a blue precipitate which
dissolves in excess to give a blue solution


H + (any acid) test - correct answer - turns blue litmus
red or makes sodium carbonate effervesce (makes CO 2
gas)


H2O test - correct answer - turns white anhydrous
copper (II) sulphate into blue hydrated copper (II)
sulphate. It also turns blue anhydrous cobalt (II) chloride
into pink hydrated cobalt (II) chloride reaction is
reversible, colour changes reversed when hydrated salts
are heated.


Hydrogen (H2 ) test - correct answer - pops with a
lighted splint


insoluble black solid? - correct answer - might be
carbon (graphite), iodine or MnO 2 .