Refrigeration and Air Conditioning
The leaks in a refrigeration system using Freon are detected by

Smelling
Halide torch which on detection produces greenish flame lighting
Using reagents
Sulphur sticks which on detection gives white smoke

ANSWER DOWNLOAD EXAMIANS APP

Refrigeration and Air Conditioning
Environmental protection agencies advice against the use of chlorofluorocarbon refrigerants since

These react with ozone layer
These react with water vapour and cause acid rain
These react with plants and cause greenhouse effect
These react with oxygen and cause its depletion

ANSWER DOWNLOAD EXAMIANS APP