Name the product(s) formed on heating coal in the absence of air.
Name the products formed when :
(a) wood is burnt in the absence of air.
(b) bone is heated in the absence of air.
(c) diamond is burnt in air at 900∘C.
(d) graphite is subjected to high pressure and 3000∘ C temperature.
Name the products(s) formed on heating sugar strongly in the absence of air.
Heating of coal in the absence of air is known as: