for that o/n 2003 question:
answer: same masses of crushed coal are placed in three crucibles. a bent tube is connected from each pot to three conical flsks containing equal volumes of potassium decromate (vi). each coal sample is burnt by subjecting it to heat from a bunsen burner. the crucibles may be covered with lids to prevent escape of gases, with one hole in the lid to fit bent tube.as coal sample burns, the gas evolved reaches the potasiium dichromate (vi) solution. the heat supply is immeaditly stopped as the solution changes colour from orange to green.the new masses of the burnt coal is found and subtracted from the initial masses. the least value obtained from a coal sample is the one which produces most sulphur dioxide gas.
(ofcourse some of u may choose 2 measure the time for colour change instead of finding the masses.in this case the one with the least time would b the coal producing the highest amount of SO2)
