When copper pyrites is roasted in excess of air, a mixture of CuO + FeO is formed. FeO is present as impurity. This can be removed as slag during reduction of CuO. The flux added to form slag is
(a) Classify following oxides as neutral, acidic, basic or amphoteric:
CO, B2O3, SiO2, CO2, Al2O3, PbO2, Tl2O3
(b) Write suitable chemical equations to show their nature.