Answer:
Given
mass of solute (m) =50g
volume of water( v) 213m
Sln we Know density of water 1g/ml
find mass of water
D=m/v
1g/ml=m/213ml (divided by 213 ml both sides)
m =4.69xe-3
mass of solvent =4.69xe-3
mr of NaCl=23+35.5
mr=58.5
Form our formula of Malality
M=50x1000/58.5x4.69xe-3
M=182.24e3