Hydrogen Test - 8

Ortho and para hydrogen show different spin in a hydrogen molecule it does not show hydrogen isotopes.

Group 13 elements form hydrides of the type MH₃. Thermal stability of hydrides decreases as we move down the group. Hydrides act as weak lewis acids.

The hydrides of group -13 form electron-deficient compounds. They act as Lewis acids (electron acceptors). Ex: BH₃, AlH₃

Metallic hydrides are binary compounds of hydrogen with d- and f- block elements. Metallic hydrides are deficient in hydrogen and are almost always non-stoichiometric.

The composition of these hydrides does not correspond to simple whole number ratio and also varies with change in temperature and pressure and hence these hydrides are called non stoichiometric hydrides.

The property of absorption of hydrogen on transition metals is widely used in catalytic reduction. Metallic hydrides are conductors of heat and electricity and are harder than the parent metal

It is small in size. Its atomic no. is 1

Sodium hydride is a strong base. It is dangerous when wet because it reacts violently with water forming flammable/ explosive gas (hydrogen). The equation for the reaction involved is given by

NaH_(s) + H₂O_(l) → NaOH_(aq) + H_2(g)

30% of weight by volume(w/v) hydrogen peroxide or 100 volume strength hydrogen peroxide is perhydrol.

Perhydrol is a mild antiseptic used on the skin to prevent infection of minor cuts, scrapes, and burns. It may also be used as a mouth rinse to help remove mucus or to relieve minor mouth irritation (e.g., due to canker/ cold sores, gingivitis). This product works by releasing oxygen when it is applied to the affected area. The release of oxygen causes foaming, which helps to remove dead skin and clean the area.

Rocket Fuel used in space research is H₂ Because of following reasons:

• High specific impulse: In combination with liquid oxygen, it produces highest specific impulse.
• High exhaust velocity : This is the single most important performance goal and is related to the heat of combustion of the fuel and the molecular mass of the combustion products. Hydrogen surpasses all other chemical fuels in exhaust velocity.
• High reaction rate : Rapid reaction of fuel and oxidizer over a wide range of conditions is advantageous in converting the energy content of a chemical fuel to heat in a minimum volume. Hydrogen has high flame speed, low ignition energy, and wide flammability limits.
• Combustion chamber cooling: Combustion chamber can be regeneratively cooled by liquid hydrogen being a cryogenic fuel.

Stoichiometric compounds of dihydrogen are formed with s-block elements.

Metallic hydrides are usually nonstoichiometric compounds, as expected from their relatively low heats of formation and the mobility of hydrogen. They are ordinarily described, chemically, in terms of any of three models in which hydrogen is considered a small interstitial atom, a proton, or a hydride anion.