Question

The forensic technician at a crime scene has just prepared a luminol stock solution by adding 15.0 g of luminol into a total volume of 75.0 mL of H2O. What is the molarity of the stock solution of luminol?

Answer 1

Answer:

1.13 M.

Explanation:

• Molarity (M) is defined as the no. of moles of solute dissolved in a 1.0 L of the solution.

M = (no. of moles of luminol)/(Volume of the solution (L).

∵ no. of moles of luminol = (mass/molar mass) of luminol = (15.0 g)/(177.16 g/mol) = 0.085 mol.

Volume of the solution = 75.0 mL = 0.075 L.

∴ M = (no. of moles of luminol)/(Volume of the solution (L) = (0.085 mol)/(0.075 L) = 1.13 M.