Answer:
1.13 M.
Explanation:
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.