Which of the following ores is concentrated by the froth flotation process?

Name the reagent that is used in leaching of gold.

The role of depressants in the Froth Flotation method is to $.....$.

For the purification of alumina,the modern processes most useful when $(i)$ the impurity present is a lot of iron oxides and $(ii)$ the impurity present is a lot of silica,are:

Which soluble substances are obtained when bauxite is treated with a solution of $NaOH$ at a temperature of $473 - 523 \ K$ and a pressure of $35 - 36 \ bar$?

Which of the following ores is concentrated using a group $1$ cyanide salt?