What is the molarity of a solution that is 26.0% by mass phosphoric acid (H₃PO₄) and that has a density of 1.155 g/mL? A) 2.30 × 10^-3 M B) 2.30 M C) 2.65 M D) 3.06 M E) 0.265 M

Question

Quizplus · Accepted Answer

First, we need to find the molar mass of phosphoric acid:

H3PO4 = (3 x 1.01 g/mol) + 30.97 g/mol + (4 x 16.00 g/mol) = 98.00 g/mol

Next, we need to determine the mass of phosphoric acid in 100 g of the solution:

100 g solution x 0.26 = 26 g H3PO4

Now we can use the molar mass and mass of H3PO4 to find the number of moles:

26 g H3PO4 x (1 mol H3PO4/98.00 g H3PO4) = 0.265 moles H3PO4

Finally, we can use the volume and density of the solution to find the molarity:

density = mass/volume
volume = mass/density = 100 g/1.155 g/mL = 86.580 mL = 0.086580 L

molarity = moles of solute/volume of solution in liters
molarity = 0.265 mol/0.086580 L = 3.06 M

Therefore, the correct answer is D, 3.06 M.

What Is the Molarity of a Solution That Is 26