Q1. Why ordinary hydrogen is les reactive? OR Q2. Why reactions of ordinary hydrogen are slow?

Q1. Why ordinary hydrogen is les reactive?

                OR

Q1. Why reactions of ordinary hydrogen are slow?

Ans: ordinary hydrogen is diatomic –molecule (H₂) and two atoms in molecule hydrogen are held together by strong covalent bonds. Therefore ordinary hydrogen molecules are very stable and dissociate at extreme condition. Due to this reason, the reactions of ordinary hydrogen are very slow or it is less reactive

PROPERTIES OF POLYMERIC HYDRIDES

PROPERTIES OF POLYMERIC HYDRIDES

1. These hydrides are formed by first two elements of IIA group i.e. Be and Mg.

2. The formulas of these hydrides are (B_eH₂)_n  and (MgH₂)_n

3. In these hydrides large number of Be H₂ or MgH₂ molecules are polymerized, hence these hydries are called as “polymeric” hydrides.

4. The structural of these hydrides are given below

5. The Properties of these hydrides are in intermediate between ionic and covalent hydrides.

PROPERTIES OF METALLIC HYDRIDES OR INTERSTITIAL HYDRIDE

PROPERTIES OF METALLIC HYDRIDES OR INTERSTITIAL HYDRIDE

1. These hydrides are formed by the element of  IB to VIII groups i.e. d block element.

2. These hydrides are called as metallic hydrides because they retain the properties of metals.

3. These hydrides are solids possess high melting points.

4. The hydrides on heating loose hydrogen and leaving behind metal unchanged.

5. Transition elements such as Ni, Pt, Pd etc, hide hydrogen in empty spaces between metal atoms in        their structures, which are called as interstitial spaces. Due to this reason, these hydrides are called as “interstitial hydrides”.

6. These hydrides don’t  show definite atomic ratio in metal to hydrogen atoms and are not stoichiometric in nature.

For Example

                                                Zr₁  H_1.22 and  T_i.l H_1.7.

7. Since metallic hydrides are formed hydrides are formed due to occlusion (adsorption of hydrogen in the metals, hence these release hydrogen in atomic state on heating hence they are used as catalyst in hydrogenation reaction.