[doublek1229]

We did a lab in which we first made a grignard reagent and then convered it into benzoic acid.

The formula for the first reaction was Bromobenzene+MG ---> Grignards Reagent

Then we convered that by reacting with CO2 (dry ice) and hydrolysis with H30.  creating Benzoic Acid.

How would I do a percent yield for this reaction?

We started with
.86 g bromobenzene (MW 157)
.15 g Magnesium (MW 24.3)
and formed Grignards Reagent (MW 181.3)

Then... reacted that product with
4g CO2 (MW 44.0)
and then Hydrolized it to create benzoic acid (MW 122.13)

Can someone show me the formula for a calculation like this!  Thanks!

[Borek]

This is just stoichiometry and limiting reagent problem.

Assuming everything else is in excess 1 mole of bromobenzene should give 1 mole of benzoic acid. That's your theoretical yield.