test for ions

Question 1

Q: What is a cation?

Answer 1

A: A positively charged ion.

Question 2

Q: What is an anion?

Answer 2

A: A negatively charged ion.

Question 3

Q: What is the test for hydrogen gas?

Answer 3

A: Light a splint → hydrogen gives a squeaky pop.

Question 4

Q: What is the test for oxygen gas?

Answer 4

: Insert a glowing splint → it relights.

Question 5

Q: What is the test for carbon dioxide gas?

Answer 5

A: Bubble through limewater → turns milky/cloudy.

Question 6

: What is the test for ammonia gas?

Answer 6

A: Turns damp red litmus paper blue.

Question 7

Q: What is the test for chlorine gas?

Answer 7

A: Turns damp blue litmus paper red then bleaches it white.

Question 8

Q: Flame colour of Na⁺?

Answer 8

A: Yellow

Question 9

Q: Flame colour of Li⁺?

Answer 9

A: Red

Question 10

Q: Flame colour of K⁺?

Answer 10

A: Lilac

Question 11

Q: How do you carry out a flame test?

Answer 11

A: Clean a nichrome wire in acid → dip in sample → place in blue Bunsen flame → observe flame colour.

Question 12

Q: Flame colour of Ca²⁺?

Answer 12

A: Orange-red

Question 13

Q: Flame colour of Cu²⁺?

Answer 13

A: Blue-green

Question 14

(cation) Q: Test for Ammonium using sodium hydroxide?

Answer 14

(NH₄⁺)
A: Add NaOH → warm → ammonia gas produced, test with damp red litmus → turns blue.

Question 15

(cation) Q: What precipitate forms when NaOH is added to copper (ll)?

Answer 15

Copper(II) (Cu²⁺)
A: Blue precipitate

Question 16

(cation) Q: What precipitate forms when NaOH is added to iron 2 ?

Answer 16

Iron(II) (Fe²⁺)
A: Green precipitate

Question 17

(cation)
Q: What precipitate forms when NaOH is added to iron 3⁺?

Answer 17

Iron(III) (Fe³⁺)
A: Brown precipitate

Question 18

(Anions)Q: Test for chloride ions?

Answer 18

(Cl⁻)

A: Add acidified silver nitrate → white precipitate of silver chloride.

Question 19

(Anions)
Q: Test for bromide ions?

Answer 19

(Br⁻)
A: Add acidified silver nitrate → cream precipitate.

Question 20

(Anions)
Q: Test for iodide ions?

Answer 20

(I⁻)
A: Add acidified silver nitrate → yellow precipitate.

Question 21

Q: Test for sulfate ions?

Answer 21

(SO₄²⁻)
A: Add acidified barium chloride → white precipitate of barium sulfate.

Question 22

Q: Test for carbonate ions?

Answer 22

(CO₃²⁻)
A: Add hydrochloric acid → carbon dioxide produced → limewater turns cloudy.

Question 23

Tests for Water
Chemical test
Q: Test for water using anhydrous copper(II) sulfate ?

Answer 23

(CuSO₄)
A: Turns white → blue.

Question 24

Physical test
Q: Test for pure water?

Answer 24

A: Boils at 100°C; freezes at 0°C.