Question

If 0.650 mL of benzaldehyde reacts with enough of the Grignard reagent, calculate the theoretical yield (in grams) of the alcohol product. Show calculation with units for full credit.

Answer 1

Theoretical yield of 1-Phenyl-1-propanol in grams = 0.871 g

Step-by-step explanation:

A Grignard reagent is any of the numerous organic derivatives of magnesium (Mg) which are commonly represented by the general formula RMgX (where R is a hydrocarbon radical e.g. methyl, ethyl, propyl, etc.; and X is a halogen atom, e.g. chlorine, bromine, or iodine)

A Grignard reaction converts an aldehyde to a secondary alcohol. In the grignard reaction involving benzaldehyde as in this experiment, the grignard reagent used is ethyl magnesium bromide, EtMgBr, and the resulting product is 1-Phenyl-1-propanol, a secondary alcohol. The reaction is shown in the figure attached below.

Mass of benzaldehyde in 0.650 mL = density × volume

Density of Benzaldehyde = 1.044 g/mL

Mass of benzaldehyde = 1.044 g/mL × 0.650 mL = 0.6786 g

Molar mass of benzaldehyde = 106 g/mol

Molar mass of 1-Phenyl-1-propanol = 136 g/mol

Mass of = mass of benzaldehyde × mole ratio of 1-Phenyl-1-propanol and benzaldehyde

Mass of 1-Phenyl-1-propanol = 0.6786 g × (136 g/mol)/(106 g/mol) = 0.871 g

Therefore, the theoretical yield of 1-Phenyl-1-propanol in grams = 0.871 g