Answer
See the answer below.
Work Step by Step
a) From the chart (1 atm): $-27.5°C$
b) From the chart ($25°C$): 6.5 atm
c) The pressure in the cylinder is much greater than atmosphere's initially, but it converges to a point where they are the same. Ice forms because the temperature at which the vapor pressure is 1 atm is below the freezing point of water vapor in the air.
d) 1 and 3 are effective but dangerous, and 2 would require pumping the gas out due to the pressure being lower than the atmosphere's.
