# How to calculate the i-value of known NaCl solution, if it is isotonic with known solution of glucose?

How do I calculate the value of $$i$$ for 1.17% solution of $$\ce{NaCl}$$, if it is isotonic with 7.2% solution of glucose?

I actually do not know where to start in this question. is it possible to calculate the value of $$i$$ of $$\ce{NaCl}$$? is value of $$i$$ of glucose 1? I tried putting the osmotic pressures equal but the value of $$i$$ remains a suspense.

• Have a read through en.wikipedia.org/wiki/Van_%27t_Hoff_factor. Generally, in case of questions in books, it is assumed that the dissociation (or association) is complete, i.e. the NaCl exists only as $\ce{Na+}$ and $\ce{Cl-}$ in the solution. See if you get the solution. – Shoubhik R Maiti Jul 25 '19 at 15:33
• Consider $\pu{100 mL}$ solution of each. That means, the number of particles in $\pu{7.2 g}$ of glucose is equivalent to the number of particles in $\pu{1.17 g}$ of $\ce{NaCl}$. So, you can find the $i$ value of $\ce{NaCl}$ (you may need to assume $i=1$ for glucose). – Mathew Mahindaratne Jul 25 '19 at 17:33