Identification of Ions and Gases

Question 1

Flame Test: Lithium

Answer 1

Bright Red

Question 2

Flame Test: Sodium

Answer 2

Golden yellow/orange

Question 3

Flame Test: Potassium

Answer 3

Lilac (Light Purple)

Question 4

Flame Test: Copper

Answer 4

Blue-Green

Question 5

Flame Test: Calcium

Answer 5

Orange-Red

Question 6

Flame Test: Barium

Answer 6

Green

Question 7

Flame Test Procedure

Answer 7

In a flame test, a piece of nichrome wire is dipped into concentrated hydrochloric acid (to clean), then into the solid compound, and then into a blue Bunsen flame. The color seen in the flame identifies the metal ion in the compound.

Question 8

Addition of NaOH or NH4OH: Aluminium

Answer 8

NaOH: White ppt
Excess NaOH: Dissolves
———————————————-
NH4OH: White ppt
Excess NH4OH: Insoluble

Question 9

Addition of NaOH or NH4OH: Calcium

Answer 9

NaOH: White ppt
Excess NaOH: Insoluble
———————————————-
NH4OH: White ppt
Excess NH4OH: Insoluble

Question 10

Addition of NaOH or NH4OH: Chromium (III)

Answer 10

NaOH: Green ppt
Excess NaOH: Dissolves
———————————————-
NH4OH: Green ppt
Excess NH4OH: Dissolves

Question 11

Addition of NaOH or NH4OH: Copper (II)

Answer 11

NaOH: Light Blue ppt
Excess NaOH: Insoluble
———————————————-
NH4OH: Light Blue ppt
Excess NH4OH: Dissolves to form Royal Blue Solution

Question 12

Addition of NaOH or NH4OH: Iron (II)

Answer 12

NaOH: Green ppt
Excess NaOH: First insoluble, then turns Reddish-Brown
———————————————-
NH4OH: Green ppt
Excess NH4OH: First insoluble, then turns Reddish-Brown

Question 13

Addition of NaOH or NH4OH: Iron (III)

Answer 13

NaOH: Reddish-Brown ppt
Excess NaOH: Insoluble
———————————————-
NH4OH: Reddish-Brown ppt
Excess NH4OH: Insoluble

Question 14

Addition of NaOH or NH4OH: Zinc

Answer 14

NaOH: White ppt
Excess NaOH: Dissolves
———————————————-
NH4OH: White ppt
Excess NH4OH: Dissolves

Question 15

Identification of Ammonia Ion

Answer 15

1. Solution dissolved in water
2. Then treated with NaOH
3. Heat gently
4. Damp red litmus paper turns blue

Question 16

Identification of Carbonates

Answer 16

1. Dilute acid is added to the solid
2. Gas produced is passed through limewater
3. If the limewater goes cloudy/milky, the solid is a carbonate.

Question 17

Identifying Anions: Chloride

Answer 17

1. Add Dilute Nitric Acid
2. Add Silver Nitrate Solution
   Result: White Precipitate

Question 18

Identifying Anions: Bromide

Answer 18

1. Add Dilute Nitric Acid
2. Add Silver Nitrate Solution
   Result: Cream Precipitate

Question 19

Identifying Anions: Iodide

Answer 19

1. Add Dilute Nitric Acid
2. Add Silver Nitrate Solution
   Result: Yellow Precipitate

Question 20

Identifying Anions: Sulfate

Answer 20

1. Add Dilute Hydrochloric Acid or Dilute Nitric Acid
2. Add Barium Chloride or Nitrate Solution
   Result: White Precipitate

Question 21

Identifying Anions: Nitrate

Answer 21

1. Add NaOH solution and warm
2. Add aluminium foil or powder
3. Test gas with damp red litmus paper
   Result: Red litmus paper turns blue

Question 22

Identifying Anions: Sulfite

Answer 22

1. Add Dilute Hydrochloric Acid
2. Warm the mixture
   Result: Filter paper soaked in potassium manganate (VII) turns from purple to colorless.

Question 23

Identification of Gases: Hydrogen

Answer 23

Test: Lighted Splint
Result: Pop sound

Question 24

Identification of Gases: Oxygen

Answer 24

Test: Glowing Splint
Result: Splint relights

Question 25

Identification of Gases: Carbon Dioxide

Answer 25

Test: Limewater Result: Goes cloudy/milky

Question 26

Identification of Gases: Chlorine

Answer 26

Test: Damp Blue Litmus Paper Result: Paper goes red then white (bleached)

Question 27

Identification of Gases: Ammonia

Answer 27

Test: Damp Red Litmus Paper Result: Turns Blue and a strong smell is produced

Question 28

Identification of Gases: Sulfur Dioxide

Answer 28

Test: Filter paper soaked in *acidified* potassium manganate (VII) Result: Turns from purple to colorless.