34. Ozone: Preparation:
i. It is prepared by passing silent electric discharge through pure and dry oxygen 10 – 15 % oxygen is converted to ozone.
3 O2( g) → 2 O3( g); H = + 142 kJ mol −1
Structure of Ozone: Ozone has angular structure. Both O = O bonds are of equal bond length due to resonance.
35. Sulphur: Sulphur exhibits allotropy:
a. Yellow Rhombic( α- sulphur): b. Monoclinic( β- sulphur):
α − Sulphur YZZZZZZZZZX 369K β − Sulphur
At 369 K both forms are stable. It is called transition temperature.
Both of them have S8 molecules. The ring is puckered and has a crown shape.
Another allotrope of sulphur – cyclo S6 ring adopts a chair form.
S2 is formed at high temperature( ∼ 1000 K). It is paramagnetic because of 2 unpaired electrons present in anti bonding π * orbitals
like O2