Answer:
1.36M
Explanation:
Luminol is a compound having the molecular formula as C8H7N3O2.
To know the molarity of the stock solution of Luminol, we shall carry out the following:
Step 1:
we shall calculate the number of mole in 18g of luminol. This is shown below:
Molar mass of C8H7N3O2 = (12x8) + (7x1 ) + (14x3) + (16x2)
= 96 + 7 + 42 + 32
= 177g/mol
Mass of C8H7N3O2 = 18g
Number of mole of C8H7N3O2 =..?
Mole = Mass /Molar Mass
Number of mole of C8H7N3O2 = 18/177 = 0.102 mole.
Step 2:
Conversion of 75.0 mL of H2O to Litre (L).
1000mL = 1L
Therefore, 75mL = 75/1000 = 0.075L
Step 3:
Determination of the molarity of the stock solution of Luminol.
Molarity is simply defined as the mole of solute per unit litre of water. Mathematically, it is represented as:
Molarity = mole /Volume
With the above formula, we can obtain the molarity of the stock solution of Luminol as follow:
Mole of C8H7N3O2 = 0.102 mole
Volume of water = 0.075L
Molarity =..?
Molarity = mole /Volume
Molarity = 0.102/0.075
Molarity = 1.36M
Therefore, the molarity of the stock solution of Luminol is 1.36M.
