Recognition and Identification of Gases

Flashcards for the identification of gases based on their properties and reactions.

Colour of Nitrogen dioxide gas

Deep reddish brown when hot, pale brown when cold. It is Nitrogen dioxide gas (NO2)

Colour of Chlorine

Greenish yellow. It is Chlorine (Cl₂)

Examples of Colourless gas

Hydrogen (H₂), Oxygen (O2), Ammonia (NH3), Hydrogen chloride (HCl), Sulphur dioxide (SO2), Carbon dioxide (CO2), Water vapour (H₂O)

Odour of Hydrogen chloride gas

Choking odour which causes pungent sensation in nasal cavity. It is Hydrogen chloride gas (HCl)

Odour of Chlorine gas

Greenish yellow colour and pungent odour. It is Chlorine gas (Cl₂)

Odour of Nitrogen dioxide gas

Reddish brown and has pungent and irritating odour. It is Nitrogen dioxide gas (NO₂)

Odour of Hydrogen sulphide gas

Rotten eggs like smell. It is Hydrogen sulphide gas (H₂S)

Odour of Sulphur dioxide gas

Suffocating smell like burning sulphur and causes coughing. It is Sulphur dioxide gas (SO₂)

Odour of Ammonia gas

Sharp smell which brings tears in eyes. It is Ammonia gas (NH₂)

Gases with no odour

Oxygen gas (O₂), hydrogen gas (H), water vapour (H₂O) or carbon dioxide (CO₂)

Gases that extinguish a lighted wooden splint

Carbon dioxide, Ammonia, Sulphur dioxide, Nitrogen dioxide, Chlorine, Hydrogen sulphide, Hydrogen chloride, Water vapour

Gas that makes a lighted wooden splint burn more brightly

Oxygen gas

Gas that burns with a 'pop' sound when a lighted wooden splint goes off

Hydrogen gas

Effect of ammonia on moist litmus paper

Changes moist red litmus paper to blue.It is Ammonia (NH3)

Effect of various gases on moist blue litmus paper

Turns moist blue litmus paper red. It is Carbon dioxide (CO₂), Hydrogen sulphide (H₂S), Hydrogen chloride (HCl), Nitrogen dioxide (NO)

Effect of chlorine or sulfur dioxide on moist blue litmus paper

Turns moist blue litmus paper red and then gets bleached. It is Chlorine (Cl₂) or Sulphur dioxide (SO₂)

Hydrogen Gas (H₂)

Colourless and odourless gas produced when zinc or magnesium reacts with dilute sulphuric acid.

Hydrogen Gas Test

Burns with a pale blue flame with a pop sound.

Oxygen Gas (O₂)

Colourless and odourless gas produced by heating potassium chlorate.

Oxygen Gas Test

Causes a glowing splint to burst into flame.

Carbon Dioxide Gas (CO₂)

Colourless and odourless gas produced when marble chips react with dilute hydrochloric acid.

Carbon Dioxide Gas Test

Turns limewater milky.

Hydrogen Chloride Gas (HCl)

Colourless gas with choking odour, forms dense white fumes with ammonia.

Hydrogen Chloride Test

Turns blue litmus paper red.

Sulphur Dioxide Gas (SO₂)

Colourless gas with a choking odour like burning sulphur, turns orange potassium dichromate paper green.

Sulphur Dioxide Test

Turns litmus paper red and then bleaches it.

Chlorine Gas (Cl₂)

Greenish yellow gas with a pungent odour, turns potassium iodide-starch paper blue.

Chlorine Test

Turns litmus paper red and then bleaches it.

Nitrogen Dioxide Gas (NO₂)

Reddish brown gas with a suffocating smell, turns potassium iodide-starch paper blue.

Nitrogen Dioxide Test

Turns litmus paper red.

Hydrogen Sulphide Gas (H₂S)

Colourless gas with a rotten egg smell, turns lead acetate paper black.

Hydrogen Sulphide Test

Turns litmus paper red.