Testing for Gases and Reactions

The video tutorial demonstrates how to test for four gases: chlorine, oxygen, hydrogen, and carbon dioxide. For chlorine, damp blue litmus paper turns white if chlorine is present. Oxygen is tested by inserting a glowing splint into the gas, which relights if oxygen is present. Hydrogen is identified by a squeaky pop sound when a burning splint is introduced. Carbon dioxide is tested by bubbling the gas through lime water, which turns cloudy if carbon dioxide is present. Safety precautions are emphasized, especially for chlorine.

Which gases are tested in the video?

• Chlorine, Oxygen, Hydrogen, and Carbon Dioxide

• Chlorine, Oxygen, Hydrogen, and Methane

• Chlorine, Oxygen, Nitrogen, and Carbon Dioxide

• Chlorine, Nitrogen, Hydrogen, and Carbon Dioxide

What color does damp blue litmus paper turn if chlorine is present?

• Blue

• White

• Green

• Red

Why might the litmus paper briefly turn red before turning white in the presence of chlorine?

• Because chlorine is neutral

• Because chlorine reacts with oxygen

• Because chlorine is a base

• Because chlorine forms hydrochloric acid with water

What safety precaution should be taken when testing for chlorine?

• Wear gloves

• Wear a mask or use a fume cupboard

• Use a fire extinguisher

• Wear safety goggles

What happens to a glowing splint in the presence of oxygen?

• It extinguishes

• It relights

• It turns blue

• It makes a popping sound

What sound is heard when hydrogen is tested with a burning splint?

• A loud bang

• A squeaky pop

• No sound

• A hissing sound

What is formed when hydrogen burns with oxygen in the air?

• Carbon Dioxide

• Water

• Hydrochloric Acid

• Methane

What solution is used to test for carbon dioxide?

• Ammonia

• Sodium Hydroxide

• Calcium Hydroxide (Lime Water)

• Sulfuric Acid

What happens to lime water when carbon dioxide is bubbled through it?

• It turns blue

• It becomes clear

• It goes cloudy

• It turns red

What solid is formed when carbon dioxide reacts with calcium hydroxide?

• Calcium Nitrate

• Calcium Sulfate

• Calcium Chloride

• Calcium Carbonate