Question

A sugar syrup of weight `214.2 g` contains `34.2 g` of sugar `(C_(12) H_(22) O_(11))`. Calculate
a. the molal concentration.
b. the mole fraction of the sugar in the syrup.

Answer 1

Correct Answer - `(9.9 xx 10^(-3))`
Moles of sugar `=34.2/342=0.1`
Moles of water in syrup`=214.2-34.2`
`=180 g`
Therefore, (i) Molarity `=("Moles of solute")/("Weight of Solvent (g)")xx1000`
`=0.1/180xx1000=0.55`
(ii) Mole fraction of sugar `=("Mole of sugar")/("Mole of sugar + Mole of water")`
`=0.1/(0.1+10)=9.9xx10^(-3)`