Testing for gases

Question 1

how do you test for oxygen

Answer 1

use a glowing splint, if it relights then oxygen is present

Question 2

how do you test for chlorine

Answer 2

using a damp litnus paper, if it goes bleached chlorine is present

Question 3

how do you test for CO2

Answer 3

bubble CO2 through limewater, if the limewater goes cloudy then CO2 is present

Question 4

how do you test for H2

Answer 4

react a metal + acid to produce H2
If we burn H2 a squeaky pop is heard