A colourless and odourless gas X burns in oxygen with a pale blue flame.
(a) Suggest two gases which X could be.
(b) Give one chemical test that could be used to confirm which of the two gases X is.
Explanation
(a) X could be carbon(II) oxide (CO) or hydrogen (H(_2)).
(b) The produce of the combustion of CO(_{(g)}) is CO(_{2(g)}) which turns lime water milky.