Testing For Gas

Question 1

O2 Gas

Answer 1

Place a glowing splint into a sample of gas.

A positive result observation will be that the splint relights.

Question 2

Cl2 Gas

Answer 2

Bring gas into contact with damp blue litmus paper/damp universal indicator paper.

A positive result observation would be that the paper turns red then bleaches.

Question 3

CO2 Gas

Answer 3

Bubble gas through limewater.

A positive result observation would be that the limewater turns from colourless to milky or cloudy white suspension. The XS CO2 causes limewater turn colourless again this means that the precipitate redissolves.

Question 4

SO2 Gas

Answer 4

Bring gas into contact with filter paper didn’t acidified potassium dichromate solution.

A positive result observation would be that the dichromate turns from orange to green colour change.

Question 5

HCl Gas

Answer 5

Bring gas into contact with glass rod Dipped concentrated ammonia.

And positive result observation would be that white fumes are formed, this is the ammonium chloride.

Question 6

NH3 Gas

Answer 6

Bring the gas into contact with glass rod Dipped concentrated hydrochloric acid.

A positive result observation for this test is that white frames are formed this is ammonium chloride

Question 7

H2 Gas

Answer 7

Place a burning splint into a sample of gas.

The positive result observation will be:
It burns with a squeaky pop.