An aqueous which is 20% (w/w) in NaOH. What will be mass fraction of water in 30ml of such solution.

Explanation

100gm solution contain `w_(NaOH)=20gm`
100 ml solution contain `w_(NaOH)=30gm`
30 ml solution contain `w_(NaOH)=(30)/(100)xx30=9gm`
20 gm NaOH present in volume of solution `=(100)/(30)xx20ml`
`d_("solution")=(100)/(100xx20)=(3)/(2)gm//ml=(w_("solution"))/(30ml)rArrw_("solution")=45gm`
`w_(NaOH)=(9)/(45)=(1)/(5)=0.2`
`w_(NaOH)=9gm`
`x_(NaOH)=(9)/(45)=(1)/(5)=0.2`
`x_(H_(2)O)=0.8`
0.8xx10=8