Question

How much ethyl alcohol must be added to `1.00 L` of water so that the solution will not freeze at `-4^(@)F` ?
A. `122`g
B. `512`g
C. `670`g
D. `495`g

Answer 1

Correct Answer - C
`-4^(@)f`is to be converted into `C^(@)`
`(F-32)/(180)=(C)/(100)` ltbr `(-6-30)/(180)=C/(100)`
`:. C=-27^(@)C`
`:. DeltaT_(f)=-27^(@)C`
1 L `H_(2)O=1000g` water
`DeltaT_(f)=(1000k_(f)w_(1))/(m_(1)w_(1))`
`w_(1)("ethyl alcohol")=(DeltaT_(f)m_(1)w_(2))/(1000k_(f))=(27xx46xx1000)/(1000xx1.86)`
`=(12466)/(186)=670g`