Hydrogen does not combine with

Which of the following statements is incorrect regarding saline hydrides?

Hydrogen has three isotopes. The number of possible diatomic molecules will be:

Which one of the following statements is not correct for ortho and para hydrogen?

Dihydrogen reacts with dioxygen $(O_2)$ to form water. Write the name and formula of the product when the isotope of hydrogen which has one proton and one neutron in its nucleus is treated with oxygen. Will the reactivity of both the isotopes be the same towards oxygen? Justify your answer.

Which one of the following would lose weight on exposure to atmosphere?