The difference in the number of water molecules in gypsum and plaster of Paris is:

Which of the following statements is not correct?

The following compounds have been arranged in order of their increasing thermal stabilities. Identify the correct order.
$K_2CO_3$ $(I)$
$MgCO_3$ $(II)$
$CaCO_3$ $(III)$
$BeCO_3$ $(IV)$

Group $2$ hydrides with significant covalent character is/are:

The order of thermal stability of carbonates of $IIA$ group is

Calcium is obtained by which of the following methods?