Excuse me sir I did not ask what density is, I do know what it is but my question was that why would we need the density.You see the main question is part of a sample exam paper there won't be any density tables whatsoever
I don't know how to get the oolarity from just the percentage
See this question:
Calculate the osmolarity of each solutions:
5% glucose solution
.89% NaCl solution
And 8% glucose solution
i=1.9