PDF Coaloal Andand Petroleumetroleum W Ncert
Coal gas is obtained during the processing of coal to get coke. It is used Coal gas was used for street lighting for the first time in London in 1810 and in New York around 1820. Now a days, it is used as a source of heat rather than light. These days, bitumen, a petroleum product, is used in place of coaltar for metalling the roads. Fig. ...