Suppose a student started with 155.0 mg of trans-cinnamic acid, 458 mg of pyridinium tribromide, and 2.35 ml of glacial acetic acid. after the reaction and workup, the student ended up with 0.2170 g of brominated product. calculate the student\'s theoretical and percent yields.

The theoretical yield of the product is 0.320 grams and its percent yield is 67.81 %

Explanation:

To calculate the number of moles, we use the equation:

     .....(1)

Given mass of trans-cinnamic acid = 155 mg = 0.155 g   (Conversion factor: 1 g = 1000 mg)

Molar mass of trans-cinnamic acid = 148.2 g/mol

Putting values in equation 1, we get:

Given mass of pyridinium tribromide = 458 mg = 0.458 g

Molar mass of pyridinium tribromide = 319.82 g/mol

Putting values in equation 1, we get:

Here, glacial acetic acid is considered as a buffer reagent so as to maintain the pH of the reaction.

By Stoichiometry of the reaction:

1 mole of trans-cinnamic acid reacts with 1 mole of pyridinium tribromide

So, 0.00104 moles of trans-cinnamic acid will react with = of pyridinium tribromide

As, given amount of pyridinium tribromide is more than the required amount. So, it is considered as an excess reagent.

Thus, trans-cinnamic acid is considered as a limiting reagent because it limits the formation of product.

By Stoichiometry of the reaction:

1 mole of trans-cinnamic acid produces 1 mole of 2,3-dibromo-3-phenyl propanoic acid

So, 0.00104 moles of trans-cinnamic acid will produce = of 2,3-dibromo-3-phenyl propanoic acid

Now, calculating the mass of 2,3-dibromo-3-phenyl propanoic acid from equation 1, we get:

Molar mass of 2,3-dibromo-3-phenyl propanoic acid = 308 g/mol

Moles of 2,3-dibromo-3-phenyl propanoic acid = 0.00104 moles

Putting values in equation 1, we get:

Experimental yield of 2,3-dibromo-3-phenyl propanoic acid = 0.217 g

Theoretical yield of 2,3-dibromo-3-phenyl propanoic acid = 0.320 g

Putting values in above equation, we get:

Hence, the theoretical yield of the product is 0.320 grams and its percent yield is 67.81 %

nacl or sodium chloride is an ionic compound. this is because an ionic compound pertains to a compound that consists of positively and negatively charged ions. in this case, na (sodium) has a tendency to lose one electron when it reacts with with other atoms, so the resulting sodium ion contains 11 protons and 10 electrons, thus making it positively charged (na+), when chlorine reacts, it usually gains one electron to form an ion called chloride, thus making it negatively charged ( since the ions are oppositely charged, they attract.