Some gases

What is the chemical formula of carbon dioxide?

• CO

• C₂O

• C₂O₂

• CO₂

Which chemical is used with limestone to prepare CO₂ in the laboratory?

• Sulphuric acid

• Nitric acid

• Hydrochloric acid

• Dilute hydrochloric acid

What type of gas is carbon dioxide regarding combustion?

• It supports combustion

• It is combustible

• It is explosive

• It neither burns nor supports combustion

What happens when moist blue litmus paper is brought near carbon dioxide?

• Turns blue

• Turns green

• No change

• Turns red

What happens when CO₂ is passed through lime water for a short time?

• Turns colourless

• Becomes milky

• No reaction

• Turns milky due to CaCO₃

What happens when excess CO₂ is passed through lime water?

• Milky colour remains

• Turns black

• Milky colour disappears

• Milky colour disappears due to Ca(HCO₃)₂

What is the nature of carbon dioxide?

• Basic oxide

• Neutral oxide

• Amphoteric oxide

• Acidic oxide

What happens when carbon dioxide reacts with water?

• Carbon monoxide is formed

• Hydrochloric acid is formed

• Ammonia is formed

• Carbonic acid is formed

Which metal reacts with CO₂ on burning to form magnesium oxide and carbon?

• Sodium

• Potassium

• Magnesium

• Magnesium

What is formed when CO₂ reacts with KOH solution?

• Potassium hydroxide

• Potassium bicarbonate

• Potassium oxide

• Potassium carbonate