Identify the cation present in chlorophyll in green plants.

Assertion $(A)$: $K$, $Rb$, and $Cs$ form superoxides.
Reason $(R)$: The stability of the superoxides increases from $K$ to $Cs$ due to the decrease in lattice energy.
The correct answer is:

Potassium superoxide on hydrolysis gives

Metals generally melt at very high temperatures. Amongst the following,the metal with the highest melting point will be $......$

Which of the following properties is $NOT$ an anomalous property of $Li$?

The solubility of metal halides depends on their nature,lattice enthalpy and hydration enthalpy of the individual ions. Amongst fluorides of alkali metals,the lowest solubility of $LiF$ in water is due to