Ethanol is added to the reaction mixture of base and fat in the manufacture of soap because it interferes with the formation of soap and making clarifying it making it translucent. It allows fatty acid to be partially mixed in the water where the base is being dissolved.
I believe a photon is the answer you are looking for.
Solid KMnO₄ needed = 7.9 g
<h3>Further explanation</h3>
Given
MW KMnO₄ = 158 g/mol
500 mL(0.5 L) of a 0.1M stock solution of KMnO₄
Required
solid KMnO₄
Solution
Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

Input the value :
n = M x V
n = 0.1 M x 0.5 L
n = 0.05 mol
Mass KMnO₄ :
= mol x MW
= 0.05 x 158 g/mol
= 7.9 g