Which of the following refrigerants is used in medium pressure appliance?

All of the following are violations of the Clean Air Act:
Falsifying or failing to keep required records.
Failing to reach required evacuation levels before opening or disposing of appliances.
Knowingly releasing CFC or HCFC refrigerants or their substitutes while repairing appliances.

Even though R-22 is considered non-toxic, it can cause asphyxia.
Asphyxiation, which is suffocation resulting from a lack of oxygen, can occur when refrigerants are released and present in mechanical rooms, confined spaces, etc.
Because the refrigerant is heavier than the oxygen you breathe, it actually displaces oxygen from the floor up and deprives you. This is why refrigerant sensors that actuate alarms and ventilation equipment are mandated for mechanical equipment rooms.

ARI 700 is a standard or publication by the Air Conditioning Heating and Refrigeration Institute and is the standard specification for refrigerants.

An appliance with an operating compressor and a completely restricted capillary tube or metering device requires only one access valve on the high side of the system. (Page 17 & 18 ESCO EPA 9TH V2 Edition Prep Manual)

All synthetic oils are hygroscopic (readily absorbs moisture) but not mineral oils.

When chlorine ion reacts with ozone molecule in stratosphere, oxygen and chlorine monoxide (clo-) are formed. Chlorine monoxide (clo-) then again reacts with ozone molecule to form oxygen and chlorine ion.

Chlorine ion at stratosphere is responsible for depletion of ozone molecules at stratosphere. HFC refrigerants do not have chlorine ions. Therefore, HFCs have minimum ozone depletion potential. However, HFC refrigerants are greenhouse gases and contribute to global warming.