a/2

a/√2

a/4

√3a/4

Lane’s process

Bosch process

From natural gas

All of these

${\rm{N}}{{\rm{H}}_3}\;{\rm{and}}\;{{\rm{B}}_2}{{\rm{H}}_6}$

${\rm{NaH}}\;{\rm{ and }}\;{\rm{Ca}}{{\rm{H}}_2}$

${\rm{NaH }}\;{\rm{and }}\;{\rm{N}}{{\rm{H}}_3}$

${\rm{Ca}}{{\rm{H}}_2}\;{\rm{and}}\;{{\rm{B}}_2}{{\rm{H}}_6}$

Nuclear reactions

Passing steam over heated C

Action of ${\rm{NaOH}}\;{\rm{ on Al}}$

Action of ${{\rm{H}}_2}{\rm{S}}{{\rm{O}}_4}\;{\rm{on }}\;{\rm{Zn}}$

The reaction requires a large amount of heat to start.

A large amount of heat is absorbed during the reaction.

A large amount of heat is released during the reaction.

The reaction proceeds very slowly.

A single hydrogen atom

Two hydrogen atoms bonded together

Three hydrogen atoms bonded together

A mixture of hydrogen and other elements

Helium

Bismuth

Antimony

Sodium

Only para hydrogen exists

Only ortho hydrogen exists

Both para and ortho hydrogen exist

None of the above

Colourless gas

Odourless gas

Tasteless gas

Non-inflammable gas

${\rm{B}}{{\rm{r}}_2}$

${{\rm{F}}_2}$

${{\rm{I}}_2}$

${\rm{C}}{{\rm{l}}_2}$

ordinary ${{\rm{H}}_2}$

${{\rm{O}}_2}$

nascent ${\rm{H}}$

${{\rm{H}}_2}$