\n4) Distillation<\/td>\n | Zinc<\/td>\n<\/tr>\n<\/tbody>\n<\/table>\n Question 6. \nWhat is the Ellingham diagram? Mention its application. \nAnswer: \nIt is a graph showing the variation of \u2206r<\/sub>G\u00b0forthe formation of oxides with temperature. It helps in the choice of reducing agent in the reduction of oxides.<\/p>\nQuestion 7. \nAlthough thermodynamically feasible, in practice, magnesium metal is not used for the reduction of alumina in the metallurgy of Aluminium. Why? \nAnswer: \nThe process would be uneconomic because Mg itself is a costly metal. Moreover, there is one technological difficulty also. The reaction between Mg and Al2<\/sub>O3<\/sub> is exothermic. If the temperature increases to 2000 K then the reverse reaction becomes feasible, i.e., Al starts reducing MgO. \n<\/p>\nQuestion 8. \nDistinguish between mineral and ore. \nAnswer:<\/p>\n \n- Mineral: Various compounds of metals which are found in earth\u2019s crust.<\/li>\n
- Ores: The minerals from which metal can be easily and economically extracted.<\/li>\n<\/ul>\n
Question 9. \nWhich flux can be used to remove a metal oxide impurity from a sulphide ore of noble metal? Substantiate. \nAnswer: \nSilica, SiO2<\/sub>. Generally, metal oxides are basic in nature. To remove basic impurities an acidic flux like SiO2<\/sub> is used.<\/p>\nQuestion 10. \nMatch the following: \n \nAnswer:<\/p>\n |