In Bosch's process,which gas is utilised for the production of hydrogen gas?

Which of the following forms of hydrogen emits low energy $\beta^{-}$ particles?

When steam is passed over red hot iron,the substances formed are

Identify the correct statements from the following.
$(i)$ $Zn$ reacts with dilute $HCl$ and aqueous $NaOH$ solution separately and liberates hydrogen.
$(ii)$ $Ti$ and $Zr$ form interstitial hydrides.
$(iii)$ The viscosity of $H_2 O$ is more than the viscosity of $D_2 O$.

Which of the following substances can be used for drying gases?

The number of neutrons in heavy hydrogen is ......... .