An element X burns with a brilliant blue flame in the presence of oxygen to form Y.Y turns acidified potassium dichromate paper green. Identify X and Y.

Options

A. nitrogen, nitrogen dioxide
B. sulphur, sulphur dioxide
C. phosphorus, phosphorus pentoxide
D. sodium, sodium oxide

Answer

B

Explanation

Sulphur is the non-metal which burns with a blue-coloured flame. `SO_2` turns orange-coloured `K_2 Cr_2O_7` green due to the formation of `Cr(SO_4)_3` .