Question

Sucrose is very soluble in water. at 25◦c, 211.4 grams of sucrose will dissolve in 100 g of water. given that the density of the saturated sucrose solution is 1.34 g/ml, what is the molarity of the solution

Answer 1

Molarity of solution is mathematically expressed as,
M = $\frac{x\text{weight of solute(g)}}{\text{Molecular weight X Volume of solution(l)}}$

We know that volume = mass/density
Given: mass of solution = 100 g, Density = 1.34 g/ml
∴ volume = 100/1.34 = 88.49 ml = 0.08849 l

Also, we know that molecular weight of sucrose = 342.3 g/mol
 ∴M = $\frac{x\text{211.4}}{\text{342.3 X 0.08849}}$
       = 6.979 M

Thus, molarity of solution is 6.979 M