Question

What is the molarity of a 49% $H_{3}P{O}_4$ solution by mass?
(Density of the solution = 1.33 g/mL)

• A. 0.66 M
• B. 4.9 M
• C. 6.65 M
• D. 5 M

Answer 1

The correct option is C 6.65 M

Mass of the solute in 1000 g of the solution = 490 g
Volume of 1000 g of the solution = $\frac{Mass}{Density}=\frac{1000}{1.33}=751.88$ mL
$Molarity=\frac{\text{Number of moles of solute}}{\text{volume of solution in L}}=\frac{490\times 1000}{98\times 751.88}=6.65M$