HYDROGEN
o Fe3O4 + 4H2 3Fe + 4H2O (On Heating)
o CuO+H2 Cu + H2O (On Heating)
o Just like alkali metals hydrogen combines with electronegative elements
such as halogen, Oxygen, Sulphur, etc. to form compounds with similar
formulae
HALIDES OXIDES SULPHIDES
HCl H2O H2 S
NaCl Na2O Na2S
o Ionization enthalpy of Hydrogen is very high- 1312 kJ mol-1.
o H+ ion doesn’t exist freely in aqueous solution- due to very small size-
therefore exist in aqueous solution in form of hydrated proton- H9O4+ or
H3O+.
o Alkali metal ions- exist as Hexahydrated ions.
o ATOMICITY- Exist in diatomic state- atomicity=2
o Electrolysis of LiH, CaH2, etc.- molten state hydrogen evolved at anode-
indicating electronegative nature.
o
Less
tendency of
hydride-
formation
DIFFEREN Nature of
Absence of CE FROM oxides-
unshared HALOGEN Neutral for
electrons S hydrogen
Nature of
Compounds-
Hydrogen
Halides- low
boiling covalent
compounds
, HALIDES: CCl4 SiCl4 GeCl4
HYDRIDES: CH4 SiH4 GeH4
o Ionization energy of hydrogen-comparable to- that of halogens.
o ORTHO HYDROGEN- Same spin
PARA HYDROGEN- Opposite spin
- Only differ in physical properties-
same chemical properties.
o
Saline
OR
Ionic
-Used as reducing
agent
Interstitial
OR
Covalent Metallic
OR
Molecular HYDRIDES -In Grp-6: Only CrH
-High electronegativity -Rest transition metals
-Always non-
stoichiometric
o Uses of Hydrogen: -
1. Synthesis of ammonia, methyl alcohol.
2. Metal like Pt, Pd has the property to store large volume of hydrogen on
its surface.
3. For generating electrical energy in fuel cell.
4. Used to reduce heavy metal oxides to metals.
o High purity H2 is obtained by electrolyzing warm aq. Ba(OH)2 solution b/w
nickel electrodes. (IMPORTANT)
o H2 2H [Fav Cond.- 1. High Temperature
2. Low Pressure]
o Fe3O4 + 4H2 3Fe + 4H2O (On Heating)
o CuO+H2 Cu + H2O (On Heating)
o Just like alkali metals hydrogen combines with electronegative elements
such as halogen, Oxygen, Sulphur, etc. to form compounds with similar
formulae
HALIDES OXIDES SULPHIDES
HCl H2O H2 S
NaCl Na2O Na2S
o Ionization enthalpy of Hydrogen is very high- 1312 kJ mol-1.
o H+ ion doesn’t exist freely in aqueous solution- due to very small size-
therefore exist in aqueous solution in form of hydrated proton- H9O4+ or
H3O+.
o Alkali metal ions- exist as Hexahydrated ions.
o ATOMICITY- Exist in diatomic state- atomicity=2
o Electrolysis of LiH, CaH2, etc.- molten state hydrogen evolved at anode-
indicating electronegative nature.
o
Less
tendency of
hydride-
formation
DIFFEREN Nature of
Absence of CE FROM oxides-
unshared HALOGEN Neutral for
electrons S hydrogen
Nature of
Compounds-
Hydrogen
Halides- low
boiling covalent
compounds
, HALIDES: CCl4 SiCl4 GeCl4
HYDRIDES: CH4 SiH4 GeH4
o Ionization energy of hydrogen-comparable to- that of halogens.
o ORTHO HYDROGEN- Same spin
PARA HYDROGEN- Opposite spin
- Only differ in physical properties-
same chemical properties.
o
Saline
OR
Ionic
-Used as reducing
agent
Interstitial
OR
Covalent Metallic
OR
Molecular HYDRIDES -In Grp-6: Only CrH
-High electronegativity -Rest transition metals
-Always non-
stoichiometric
o Uses of Hydrogen: -
1. Synthesis of ammonia, methyl alcohol.
2. Metal like Pt, Pd has the property to store large volume of hydrogen on
its surface.
3. For generating electrical energy in fuel cell.
4. Used to reduce heavy metal oxides to metals.
o High purity H2 is obtained by electrolyzing warm aq. Ba(OH)2 solution b/w
nickel electrodes. (IMPORTANT)
o H2 2H [Fav Cond.- 1. High Temperature
2. Low Pressure]
