The total number of isotopes of hydrogen and the number of radioactive isotopes among them,respectively,are:

Deuterium resembles hydrogen in properties but:

Given below are two statements: one is labelled as Assertion $A$ and the other is labelled as Reason $R$.
Assertion $A:$ Hydrogen is an environment-friendly fuel.
Reason $R:$ Atomic number of hydrogen is $1$ and it is a very light element.
In the light of the above statements,choose the correct answer from the options given below:

In which of the following reactions,hydrogen is acting as an oxidising agent?

Hydrogen burns in air with a

Discuss the consequences of high enthalpy of $H-H$ bond in terms of chemical reactivity of dihydrogen.