Question

To what temperature must propane be cooled to remain a liquid at standard sea level?

any temperature below 40°C
any temperature above -42°C
at or below -42°C
below 20°C

Answer 1

Boils at -40 C (or F, same same) so colder than that it would be a clear stable liquid.

Answer 2

At or below -42°C

Step-by-step explanation:

Hello,

As propane is gaseous at the standard sea level wherein the atmospheric pressure is 1 atm and the environmental temperature roughly 25°C, in order to condense it, say convert it from gas to liquid, one must cool it down at least until its boiling temperature which is -42°C. In such manner, to remain as a liquid, it must be cooled down at or below 42°C.

Best regards.