Chemical Process
Platinum catalyst used in the earlier days of sulphuric acid manufacture by contact process suffers from the drawback like

All of these
Easy poisoning tendency
Fragile nature
High cost

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Chemical Process
Liquefaction of gases can not be done by

Exchange of heat with colder stream
Merely compressing it beyond critical pressure
Adiabatic expansion against a piston or in a turbine
Adiabatic expansion through a throttle valve (Joule-Thomson expansion)

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