Deuterium resembles hydrogen in properties but:

Which of the following sets are correctly matched?
$(i)$ $B_2H_6$ - electron deficient hydride
$(ii)$ $NH_3$ - electron precise hydride
$(iii)$ $H_2O$ - electron rich hydride

Write the physical properties of $H_2$.

$H_2SO_4$ acts as a dehydrating agent in its reaction with:

How many of the following statements is/are correct?
$(a)$ Mercury is the only metal that exists as liquid at room temperature.
$(b)$ Among non-metals,carbon has the highest melting point.
$(c)$ Hydrogen is the most abundant element in the universe.
$(d)$ Oxygen is the most abundant element in the earth's crust.

Write the isotopes of hydrogen and specify the number of protons,electrons,and neutrons in each.