Tonicity question?

Question

Can I calculate tonicity with molarity instead of osmolarity when I'm dealing with glucose and water?
I'm trying to calculate the tonicity of a fruit or vegetable w/glucose. I read that since glucose still retains its molecular structure in water, it is okay to use molarity instead of osmolarity.
I'm still a little bit confused about tonicity. Is there a specific quintative unit to describe tonicity or is it just classified into isotonic, hypertonic and hypotonice? So how would I determine the tonicity of a certain fruit or vegetable?

And which fruit or vegetable has a good amount of glucose?

Answer 1

Saline is isotonic. It is 0.85% NaCl, or 150 mM. NaCl produces two particles (ions) Na and Cl when dissolved in water. Glucose is not dissociated into two ions, so to make an isotonic glucose solution, you will need to make a 300 mM solution. For MgCl2, 100 mM is isotonic.

Osmolarity is expressed as osmoles/liter. For a pure compound, you can calculate the osmolarity from its molarity. For natural samples, like fruit juice, you will have to use an instrument to determine the osmolarity.

Grape has a good amount of glucose.

Answer 2

ya