Question

List four chemical properties of hydrogen gas.

Answer 1

Hydrogen:

• Hydrogen is a chemical element having an atomic number equal to one.
• It was discovered by Henry Cavendish.
• It is a gas with no color and odor and has the lowest density of all gases.
• It is a highly inflammable gas.
• It exists in the diatomic form in nature so 2 atoms of hydrogen make one molecule ${\mathrm{H}}_2$.

Chemical properties of hydrogen:

Hydrogen is quite reactive gas and its reactions are as follows:

(a) Reaction with Oxygen:

Hydrogen reacts with oxygen to form water or steam and this reaction is highly exothermic in nature so hydrogen burns with a pop sound.

For example, the reaction is as $2{\mathrm{H}}_2\left(\mathrm{g}\right)+{\mathrm{O}}_2\left(\mathrm{g}\right)\to 2{\mathrm{H}}_2\mathrm{O}\left(\mathrm{g}\right)$

(b) Reaction with Halogens:

Hydrogen reacts with halogens (Chlorine, Bromine, Iodine) to give hydrogen halides which are acidic in nature.

For example, the reaction is as: ${\mathrm{H}}_2\left(\mathrm{g}\right)+{\mathrm{Cl}}_2\left(\mathrm{g}\right)\to 2\mathrm{HCl}\left(\mathrm{g}\right)$

(c) Reaction with Metals:

Hydrogen reacts with some metals to form their respective hydrides.

For example, the reaction is as: $2\mathrm{Na}\left(\mathrm{s}\right)+{\mathrm{H}}_2\left(\mathrm{g}\right)\to 2\mathrm{NaH}\left(\mathrm{aq}\right)$

(d) Reaction with Sulfur:

Hydrogen reacts with Sulfur to form hydrogen sulfide gas which smells like rotten eggs.

For example, the reaction is as: ${\mathrm{H}}_2\left(\mathrm{g}\right)+\mathrm{S}\left(\mathrm{s}\right)\to {\mathrm{H}}_2\mathrm{S}\left(\mathrm{g}\right)$