testing for gases

• what is the test for chlorine?

  chlorine bleaches litmus paper white
• what is the test for oxygen?

  flame test - a glowing splint will relight in the presence of oxygen
• what is the test for carbon dioxide?

  bubbling carbon dioxide through limewater and the water will turn cloudy
• what is the test for hydrogen?

  squeaky pop test - you hold a burning splint to the tube containing hydrogen and you will hear a pop