The chief impurity present in red bauxite is:

What is a substance called from which an element can be economically extracted?

Match the following List-$I$ (Name of the mineral) with List-$II$ (Type):
| List-$I$ | List-$II$ |
| :--- | :--- |
| $A$. Calamine | $I$. Sulphide |
| $B$. Bauxite | $II$. Halide |
| $C$. Kaolinite | $III$. Carbonate |
| $D$. Cryolite | $IV$. Oxide |
| | $V$. Silicate |

$XCl_2 \text{ (excess)} + YCl_2 \to XCl_4 + Y \downarrow ;$
$YO \xrightarrow[> 400^oC]{\Delta} \frac{1}{2} O_2 + Y$. The ore of $Y$ would be:

The oxidation state of copper is $ +1 $ in which of the following?

Cryolite is