What is theoretical yield when 15.6g of bromobenzene & 8.3g of methyl benzoate is used in a Grignard reaction.

Answer 1

Start from an equation

2PhMgBr + PhCOOMe -> Ph3COH

so you need 2 moles of the Grignard reagent to each mole of the ester. As one mole of the PhBr formed from one mole of the Grignard reagent we need 2 moles of the PhBr.

So you need to
1. calculate the molar mass of each PhBr and PhCOOMe
2. calculate the number of moles of each
3. decide which is in excess.
4. calculate the theoretical yield (moles) of Ph3COH
5. calculate the molar mass of Ph3COH
6. calculate the theoretical yield (grams) of Ph3COH