Answer:
[a]. 108 mL.
[b].
1. use HCL in washing for the neutralization of NaOH.
2. Wash with water.
3. make use of MgSO4 to remove water traces.
4. Evaporate to get the pure cyclohexane
Explanation:
The chemical equation for the reaction between 2-naphthol and Sodium hydroxide is given below as:
C₁₀H₈O + NaOH --------------------------------------------------> C10H7O⁻ Na⁺ + H₂O.
The C10H7O⁻ Na⁺ is the aqueous phase.
The molarity of Sodium Hydroxide is = [ (mass of sodium hydroxide ) ÷ molar mass sodium hydroxide × volume] × 1000.
The molarity of sodium hydroxide = [ (5/40) × 100] × 1000 = 1.25 M.
The number of moles of 2-naphthol = mass / molar mass = 20 / 144.17 = 0.138 moles.
Recall that, the formula for the number of moles = concentration × volume. Therefore, the volume of sodium hydroxide is given below as:
Volume of sodium hydroxide = the number of moles of sodium hydroxide ÷ concentration of sodium hydroxide = 0.138 ÷ 1.25 = 0.108L = 108 mL.
In order to efficiently isolate relatively pure cyclohexane from the ether layer, the following process must be followed:
1. use HCL in washing for the neutralization of NaOH.
2. Wash with water.
3. make use of MgSO4 to remove water traces.
4. Evaporate to get the pure cyclohexane
