Question

A sugar syrup weigh 212 hg contains 34.2 g of sugar calculate1)molal concentration

Answer 1

(i) Weight of sugar syrup =214.2gWeight of sugar in syrup=34.2g∴∴ Weight of water in sugar syrup=(214.2-34.2)g⇒180.0g⇒180.0gMolecular weight of sugar=(C12H22O11)(C12H22O11)=342∴∴ Molal concentration =34.2×1000342×18034.2×1000342×180=0.56=0.56(ii) Mole fraction of sugar34.2/342(180/18)+(34.2/342)34.2/342(180/18)+(34.2/342)(Mol.wt of water=18)⇒0.110+0.1=0.110.1⇒0.110+0.1=0.110.1=0.0099=0.0099Hence (a) 0.56,0.0099 is the correct option.