Calculate the freezing point of a solution containing 8.1 g of HBr in 100 g of water, assuming the acid to be 90% ionized. [Given: Molar mass Br- = 80 g/mol, Kf water = 1.86 k kg/mol]
a) -1.8°C
b) -3.6°C
c) -5.4°C
d) -7.2°C