Question

How do you calculate the percentage yield of a recrystallized product?

Answer 1

In the process of recrystallization a product is formed by eliminating its impurities. Mathematically it is the ratio of actual yield which we get after the process to the theoretical yield which could be obtained without any errors or without any loss of compound. This ratio is then multiplied by $100$ to make it in percent.

Complete answer:

When we are preparing some compounds by the addition of two or more compounds, we have to mention the yield which we get at last. By this yield we get to know how much error and how much compound we wasted sometimes. We all know that the reaction we usually wrote on paper is not exactly obtained when we try to make it in our laboratories. Many phenomena take place like that if we do not weigh the compound exactly, or may be any side reaction developed. There are many options for the loss of $100\%$ yield.
Mathematically, the ratio of actual yield to theoretical yield multiplied by $100$ to convert it in percentage. If we write in mathematical form, it comes to be like this-
$Percent\,yield = \dfrac{{Actual\,yield}}{{Theoretical\,yield}} \times \,100\%$
Now, if we try to understand it with a reaction, it will be easy for us to take an example of oxidation reaction of acetaldehyde with bromine water.
$C{H_3}CHO + B{r_2}\xrightarrow{{Oxidation}}\,C{H_3}COOH$
Here, suppose after the reaction we get (x) amount of acetic acid, but amount of product could be obtained (y) amount of acetic acid after the reaction without loss of acetaldehyde or any other error. So, here (y) is the theoretical yield while (x) is the actual yield which we get after working on this reaction in the laboratory. After putting values in the formula we can easily calculate the percent yield.

Note: While writing values in the formula make sure that you write the amount which you get in place of actual yield and the theoretical yield as the amount which you could obtain from the amount of reactants given. Don’t forget to multiply the ratio with $100$ to change it in percent, otherwise you will get an answer in decimals.