Which device may be used to throttle and vaporize liquid refrigerant before it enters the compressor?

Answer: An expansion valve.

Explanation:

The expansion valve is a copper tubing that contains a small orifice. The orifice restricts the flow of the refrigerant and makes it undergo a severe drop in pressure and temperature when it exits the orifice.

The temperature drop provides the cooling required in the cooling coils of the refrigerator.