Question

If 107 g of an aqueous solution contains 39.5g of a solute (mol. weight = 158), then mole %
of the solute is: -
(1) 2.25%
(2) 4.25%
(3) 6.25%
(4) 8.25%
​

Answer 1

Answer:

(3) 6.25%

EXPLANATION:

aqueous solution contains solute and water

no of moles of solute= 39.5/158=0.25

mass of water in solution=158-39.5=67.5 grams

therefore no of moles of water= 67.5/158=3.75

now,

mole% of solute= (no of moles of solute)•100/(no of moles of solute+no of moles of solvent)

= (0.25).(100) / (0.25+3.75)

= 6.25 percent