Question

At a coastal area, the vapor pressure of x gram of NaOH solution in 500 gram of water is 1 atmosphere at 100.2°C. if the constant boiling point of water (Kb) is 0.5°C kg/mol, what is the value of x? (Mr NaOH = 40 g/mole)

Answer 1

NaOH ----------------> Na^+ + OH^-      (i = 2)
ΔTb = 100,2 - 100 = 0,2

ΔTb = kb . m . i
0,2 = 0,52 . . . 2
0,2 = 0,52 . . . 2
8 = 0,52 . x. 2. 2
8 = 2,08x
x = 3,85 gram