(a) How is ozonised oxygen prepared in the laboratory? Give equation.
(b) Give the composition of " Oleum".

Explanation

(a) Ozone is prepared by subjecting pure and dry Oxygen to silent electric discharge
A sparkle electric discharge (silent) produce less heat. This prevent the local rise in temperature which may decompose ozone bact to oxygen.
The apparatus used for the preparation of ozone is called ozonisers are commonly used,ie. sliemen.s ozoniser and Brodies ozoniser.The description of siemen.s ozoniser is being given below.br> siemen.s ozoniser
it consists if two co axial tubrs at onr end. outer surface of the outer tube and inner surface of the inner tube is called with tin foil.The inner and outer coating of tim foil are connected to thr terminals of induction coil. One end of the co-axial tube has inlet for pure and dry oxygen,and the other end has the outlet for ozonised oxygen.br> A slow stream of pure and dry oxygen is passed through the space between the co-axial tubes and is subjected to the silent electrical discharge. Some of oxygen gets converted into ozone. The mixture containing 10-15% of ozone comes out of the outlet and is collected as such.
(b) `H_2S_2O_2`.