Which of the following metals produces hydrogen gas on reacting with cold dilute nitric acid?

The number of alkali metal$(s)$,from $Li$,$K$,$Cs$,$Rb$ having ionization enthalpy greater than $400 \ kJ \ mol^{-1}$ and forming stable super oxide is $.......$

What are the products formed when $Li_2CO_3$ undergoes thermal decomposition?

Among alkali metal salts,lithium salts are the least conducting in their aqueous solutions. This is due to:

Sodium metal reacts with $Al_2O_3$ at high temperature to give a sodium compound $X$. Compound $X$ reacts with carbon dioxide in water to give $Y$. What is $Y$?

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