4: Inorganic - Tests for Ions

Question 1

Test for hydrogen halides

Answer 1

Dissolve in water to form misty fumes of acidic gas
Damp blue litmus paper —> red
OR
React with ammonia gas to give white fumes
e.g. HCl + NH3 –> NH4Cl (s)

Question 2

Test for halide ions

Answer 2

+ dilute nitric acid
+ silver nitrate solution
—> precipitate of silver halide
AgF - soluble
AgCl - white - dissolves in dilute ammonia solution
AgBr - cream - dissolves in conc. ammonia solution
AgI - Yellow - does not dissolve

Question 3

Test for carbonates

Answer 3

+ HCl
Carbon dioxide produced
Turns limewater cloudy

Question 4

What is the sulfate ion?

Answer 4

SO₄²⁻

Question 5

Test for sulfates

Answer 5

+ dilute HCl - removes carbonate ions
+barium chloride solution
—> white precipitate of barium sulfate

Question 6

Test for ammonia gas

Answer 6

Damp red litmus paper —> blue

Question 7

Test for ammonia gas

Answer 7

+ sodium hydroxide
+ heat
—> ammonia gas given off
Damp red litmus paper —> blue