Question

Think about and describe 3 important causes of errors that can occur in the experiment of synthesis of aspirin in terms of percent yield and melting point.

Answer 1

The causes for errors in percentage yield and melting point while carrying out synthesis of aspirin are as follows:

1. While filtering out the product through buckner funnel one forgot to use 2 filter papers but instead use only one on the Buckner funnel. Hence, due to the pressure, the filter paper tore and crude product entered the filter flask that was containing the impurities and other liquid. Therefore one should suction filtrate the whole mixture in the filter flask and hence, this might have led to presence of more impurities or lose in product. This might have affected the results.

2. After obtaining the crude product from the first suction filtration, we had to transfer it to the conical flask to carry out recrystallisation. During this process, there were some crystals that got blown away by the wind and some crystals poured on the desk too. Hence this might have affected the percent yield too.

3. while taking melting point sometimes the compound is not completely dry or having impurities which can either depress or elevate the melting point depending on nature of impurity.