Question

The forensic technician at a crime scene has just prepared a luminol stock solution by adding 17.0g of luminol into a total volume of 75.0 mL of H2O.. What is the molarity of the stock solution of luminol? (Luminol has a molecular weight of 177 g/mol).

Answer 1

As we know that
M=(17*1000)/(177*75) 

m=17000/13275 

m=1.28
hope it helps

Answer 2

molarity = moles/ 1 L of solvent
17g in 75 mL = (17/75) x 1000 mL in 1000 mL = 226.66g in 1 L
moles = 226.66/177 = 1.28
∴ molarity = 1.28