Answer:
the citric acid in lemon juice is a natural bleach, or oxidizing agent. It whitens hair by chemically reducing your hair's color pigment, or melanin. When exposed to the sun, the citric acid accelerates the bleaching process
Mass of this substance = 9.928 g
<h3>Further explanation</h3>
Molarity is a way to express the concentration of the solution
Molarity shows the number of moles of solute in every 1 liter of solute or mmol in each ml of solution

Where
M = Molarity
n = Number of moles of solute
V = Volume of solution
So to find the number of moles can be expressed as

mol of substance -Lithium nitrite - LiNO₂ :
V = 250 ml = 0.25 L
M = 0.75 M

So mass of this substance - LiNO₂ (MW=52,947 g/mol) :
