(a) What are materials, X, Y and Z?
(b) When materials X, Y and Z are burned separately:
(i) Which material burns by producing a yellow, luminous flame?
(ii) Which material ultimately bums without producing a flame?
(iii) Which material can bum in a gas stove by producing a blue flame?
(b) (i) Y (wax) (ii) X (coal) (iii) Z (natural gas)