We work here with Charles' Law. The equation used here is:
V1/T1 = V2/T2 (1)
(pressure and amount constant)
V is for volume and T for temperature
V1 = 1785 mL
1 L = 1000 mL ==> V1 = 1.785 L
T1 = 25 °C = 25 °C + 273 = 298 K
V2 = 1.25 L
T2 = unknown
From (1) we clear T2:
T2 = V2 x T1/V1 = 1.25 L x 298 K/1.785 L = 209 K approx.
T2 = 209 K - 273 = -64 °C
Answer: T2 = -64 °C
