Question

Type of electric discharge used in Siemen's ozoniser = ________.

Answer 1

Preparation of ozone by Siemen's ozoniser:

Silent electric discharge is partially transformed to ozone when it is passed over dried oxygen or air in an ozoniser. The ozone content of the product obtained in gaseous form is 10-15%. Ozone is unstable because the conversion of dioxgyen to ozone is an endothermic reaction.

$3{\mathrm{O}}_2\stackrel{\mathrm{Silent}\mathrm{Electric}\mathrm{discharge}}{\rightleftharpoons }2{\mathrm{O}}_3,\mathrm{\Delta H}=+258\mathrm{KJ}$

Since ozone decomposes thermally, the yield of ozone created by passing oxygen over an electric spark is substantially lower.
The Siemen ozoniser is made up of two coaxial tubes that are joined at one end. Tin foils are used to coat the inner side of the outer tube and the outer side of the inner tube, which are connected to the two terminals of an induction coil. An ozonised oxygen outlet is located on one end of the coaxial tube. A display current of dry, cold dioxygen is passed through the tube's inlet, followed by a silent electric discharge. 10-15% of dioxygen is transformed to ozone and expelled by the exit.