determining gas tests

Question 1

test for NH3

Answer 1

• add alkali to soln, warm
• add alkali + aluminium to soln, warm

also test for NH4+

Question 2

test for CO2

Answer 2

• add acid to unknown soln

unknown soln looks like non-metal

Question 3

test for H2

Answer 3

• add acid to unknown soln

unknown soln looks like metal

Question 4

test for O2

Answer 4

• add manganese dioxide (MnO2) to unknown soln