Question

How to calculate theoretical yield benzil in the hexaphenylbenzene experiment, with 0.753 g of benzoin produced.(molecular weight of benzil is 210.28 and amount used 100ml.)

Then theoretical yield of tetraphenylcyclopentadienon with 0.264 g of benzil product.

(molecular weight of tetraphenylcyclopentadienone is 384.48 and used 100 mg)

Answer 1

Answer –

We are given, mass of benzoin = 0.753 g , molar mass of benzil = 210.28 g/mol

The reaction to find theoretical yield benzil is benzoin reacted with cupric acetate to create benzil.

So there is 1:1 mole ratio between benzoin and benzil

Step 1 ) Calculate the moles of benzoin

We know,

Moles = mass / molar mass

           = 0.753 moles / 212.24 g.mol^-1

           = 0.00355 moles

Step 2) Calculating the moles of benzil from benzoin

We know there is mole ration between benzoin and benzil is 1:1

So, moles of benzoin = moles of benzil

So, moles of benzil = 0.00355 moles

Step 3 ) Calculate theoretical yield

Theoretical yield of benzil = 0.00355 moles * 210.28 g/mol

                                            = 0.746 g

When benzil and 1,3 diphenylacetone reacted with CH3OH, [C6H5CH2N(CH3)3]+, OH- to create tetraphenylcyclopentadienone.

So, moles of benzil = moles of tetraphenylcyclopentadienon

So, moles of tetraphenylcyclopentadienon = 0.00355 moles

So theoretical yield of tetraphenylcyclopentadienon = 0.00355 moles * 384.48 g/mol

                                                                                    = 1.36 g