Question

coal tar is formed when we strongly heat coal in the absence of air and allow the gas to pass then,some particles condenses to form coal tar. so, how can coal tar be a mixture of 200 substances??

Answer 1

Coal tar is a brown or black liquid of high viscosity, which smells of naphthalene and aromatic hydro carbons. Coal tar is among the byproducts when coal is carbonized to make coke or gasified to make coal gas. Coal tars are complex and variable mixtures of phenols, polycyclic aromatic hydro carbons, and metro cyclic compounds, about 200 substances in all. Coal tar is a thick black liquid the consistency of a thick pudding. Coal tars are by metallurgical coke or natural gas.