Testing for ions and gases

Question 1

Identifying Cations

-solids, liquids

Answer 1

(Metals, positive)
SOLIDS:
1. Flame loop
2. Roaring flame
3. Observe colour change

Calcium(Ca): brick red
Lithium(Li): crimson
Sodium(Na): yellow
Potassium(K): lilac

LIQUIDS:

1. Add sodium hydroxide solution(NaOH)
2. Observe colour of precipitate

Copper sulphate(Cu): blue
Iron(ii)(Fe2+) : green
Iron (iii)(Fe3+): brown
Ammonia: colourless, smells

Question 2

Identifying Anions

Answer 2

(Non-metals, negative)
1. Add water to make a solution 
SULPHATES(SO4): 
-dilute HCL acid
-barium chloride
-White precipitate

CARBONATES (CO3):

• dilute acid
• bubbles/limewater
• turns cloudy/effervescence

HALIDES:
-dilute nitric acid
-silver nitrate solution
Chloride: while precipitate 
Bromide: cream precipitate 
Iodide: hello precipitate

Question 3

Test for hydrogen

Answer 3

A glowing splint makes a squeaky pop in a test tube

Question 4

Test for oxygen

Answer 4

A glowing splint relights

Question 5

Test for carbon dioxide

Answer 5

Turns limewater cloudy

Question 6

Test for ammonia

Answer 6

Sharp smell

Turns damp red litmus paper blue

Question 7

Test for chlorine

Answer 7

Sharp smell
Turns damp blue litmus paper red, then white
Turns damp starch-iodine paper blue-black