Bayer's process is used for the purification of Bauxite containing which of the following as an impurity?

Which of the following ores is best concentrated by the froth-flotation method?

Reagent used in Bayer's process of concentration of bauxite ore is:

Given below are two statements :
Statement $I :$ Sphalerite is a sulphide ore of zinc and copper glance is a sulphide ore of copper.
Statement $II :$ It is possible to separate two sulphide ores by adjusting proportion of oil to water or by using 'depressants' in a froth flotation method.
Choose the most appropriate answer from the options given below :

Froth floatation process is used for the concentration of the ore of

Explain the leaching of:
$(i)$ Alumina from Bauxite (Bayer's Process)
$(ii)$ Gold and Silver (Cyanide Process)