Hardening of oils is caused by

Which of the following is used to dry ammonia gas?

Which of the following orders is incorrect?

If an isotope of hydrogen has two neutrons in its atom,its atomic number and atomic mass number will respectively be

Which one of the following properties has the same value for $H_2$ and $D_2$?

Consider the following statements and identify which of them are correct:
$I.$ Atomic hydrogen is obtained by applying an electric arc to hydrogen gas.
$II.$ Hydrogen gas does not reduce heated aluminum.
$III.$ Finely divided palladium absorbs a large volume of hydrogen gas.
$IV.$ The reaction of $Na$ with $C_2H_5OH$ yields pure nascent hydrogen.