P Block Elements

Oxides of Nitrogens:

1. Nitrous oxide (N₂O)




It is used for the preparation of azides

N₂O + NaNH₂ NaN₃ + H₂O


2. Nitric oxide (NO)



The liquid and solid states are diamagnetic, because close dimers are formed






Reaction with Cl₂

2NO + Cl₂ 2NOCl
(nitrosyl chloride)


3. Nitrogen oioxide




The gas condenses to a brown liquid which turns paler on cooling and eventually becomes a colourless solid, due to dimerization.


2NO₂ N₂O₄



Liquid N₂O₄ is useful as a non - aqueous solvent. It self - ionizes


N₂O₄ NO⁺ + NO₃^-

acid base


A typical acid base reaction is
NOCl + NH₄NO₃ NH₄Cl + N₂O₄
Acid     base               salt         solvent


4. Nitrogen trioxide or nitrogen sesquioxide (N₂O₃)




N₂O₃ + H₂O 2HNO₂

(anhydride of nitrons acid)

N₂O₃ + 2HClO₄ 2NO [ClO₄] + H₂O




5. Di nitrogen pentoxide [N₂O₅]


It is the anhydride of HNO₃. It is strong oxidizing agent





Structure of Phosphorus pentoxide (P₄O₁₀)





P₄O₁₀ + 6H₂O 4H₃PO₄

(anhydride of
phosphoric acid)



Phosphorus trioxide : [P₄O₆]




P₄O₆ + 6H₂O 4H₃PO₃
(Cold)


P₄O₆ + 6H₂O PH₃ + 3H₃PO₄
(Hot)


Oxy Acids of Nitrogen

1. H2N2O2	Hyponitrous acid
2. H2 NO2	Hydronitrous acid
3. HNO2	Nitrous acid
4. HNO3	Nitric acid
5. HNO4	Per nitric acid

Oxy - Acids of Phosphorus

1. H3PO2	Hypophosphorus acid
2. H3PO3	Phosphorus acid
3. H4P2O6	Hypophosphoric acid
4. H3PO4	Orthophosphoric acid
5.H4P2O7	Pyrophosphoric acid
6. HPO3	Metaphosphoric acid

KMnO₄





FeCl₃ (gas)



>



K₂Cr₂O₇




FeCl₃6H₂O consists of trans [Fe(H₂O)₄Cl₂]Cl.2H₂O, though in strong HCl it forms tetrahedral [FeCl₄]^- ions


Oxo Acids of Sulphur

H2SO3	Sulphurous aicd
H2S2O5	di-or pyrosuphurous acid
H2S2O4	Dithionous acid
H2S2O3	Thiosulphuric acid
H2S2O7	di or pyrosulphuric acid
H2S2O6	dithionic acid
H2SnO6:	Poythionic acid (n = 1 to 12)
H2SO5	peroxyo monosulphuric acid
H2S2O8	Peroxidisulphuric acid

O₃ is an extremely powerful oxidizing agent, second only to F₂ in oxidizing power, and reacts much more readily than dioxygen


3PbS + 4O₃ 3PbSO₄

2NO₂ + O₃ N₂O₅ + O₂

S + H₂O + O₃ H₂SO₄

2KOH + SO₃ 2KO₃ + SO₂ + H₂O


Potassium ozonide KO₃ is an orange coloured solid and contains the paramagnetic ion.