$H^+$,$D^+$,and $T^+$ differ in all of the following $EXCEPT$ one.

The maximum sum of the number of neutrons and protons in an isotope of hydrogen is

Given below are two statements: one is labelled as Assertion $(A)$ and the other is labelled as Reason $(R).$
Assertion $(A):$ Heavy water is used for the study of reaction mechanism.
Reason $(R):$ The rate of reaction for the cleavage of $O-H$ bond is slower than that of $O-D$ bond.
Choose the most appropriate answer from the options given below:

Hydrogen accepts an electron to achieve the inert gas configuration. In this process,it behaves like which of the following?

$H_2S$ reacts with $O_2$ to form:

Which of the following isotopes of hydrogen has the maximum sum of $e^- + p^+ + n^0$?