Identification Of Common Gases

Question 1

How would you test for hydrogen?

Answer 1

-holding a burning splint held at the open end of a test tube of gas
-If the gas is hydrogen it burns with a loud “squeaky pop” as there is rapid combustion of hydrogen with oxygen to produce water
-Don’t splint right into the tube as the gas needs air to burn

Question 2

How would you test for oxygen?

Answer 2

• placing a glowing splint into a test tube of gas
• if oxygen is present it will relight.

Question 3

How would you test for carbon dioxide?

Answer 3

• bubble the gas through an aqueous solution of calcium hydroxide (limewater)
• if carbon dioxide is present, the limewater will turn cloudy white.

Question 4

How would you test for the presence of chlorine?

Answer 4

• hold damp litmus paper over a test tube of gas
• if chlorine gas is present, the blue paper will turn red then be bleached white.