An ore of potassium is

An element $A$ of group $1$ shows similarity to an element $B$ belonging to group $2$. If $A$ has maximum hydration enthalpy in group $1$,then $B$ is:

Which of the following has the highest tendency to undergo the following reaction?
$M^{+}_{(g)} \xrightarrow{\text{aqueous medium}} M^{+}_{(aq)}$

Arrange the following compounds in the increasing order of their thermal stability. Identify the correct sequence.
$I - K_2CO_3, II - MgCO_3, III - CaCO_3, IV - BeCO_3$

Which of the following represents the correct order of hydration energy?

$A$ mixture of lime paste is composed of sand,water,and which of the following?