Why does lithium show anomalous behavior?

When heated in air,the alkali metals form various oxides. Mention the oxides formed by $Li$,$Na$ and $K$.

What is the correct order of stability for the superoxides?

Chemically,philosopher's wool is

Compound $A$ reacts with $NH_4Cl$ and forms a compound $B$. Compound $B$ reacts with $H_2O$ and excess of $CO_2$ to form compound $C$,which on reaction with saturated $NaCl$ solution forms sodium hydrogen carbonate. Compounds $A, B$ and $C$ are respectively:

$A$ fire of lithium,sodium,and potassium can be extinguished by