(4) After addition of hydrochloric acid, a student removes the lower aqueous layer, extracts the aqueous phase with diethyl ether (0.5 mL), dries the diethyl ether layer with sodium sulfate and pours the ~0.5 mL of diethyl ether into an Erlenmeyer flask, rinsing the drying agent with more diethyl ether and pouring into the flask. Upon evaporation of the diethyl ether, the student is surprised to see no crystals present to recrystallize. Assuming Parts 1–3 were completed successfully, explain where the student lost their product.

The student did not lose any organic product in the aqueous layer

Explanation:

From the question;

After addition of hydrochloric acid, a student removes the lower aqueous layer and extracts the aqueous phase with diethyl ether (0.5 mL).

The only possible way the student could have lose the product was if there are some basic group e.g in the compound which have a tendency of forming salt.

Also these compound could be regenerated from aqueous layer by neutralizing the aqueous layer with basic solution , for example; by using sodium hydroxide (NaOH)  in which the extraction is then followed by the usage of Diethyl ether.

you need to take a look at the periodic system in order to sort these elements into pairs that would most likely exhibit similar chemical properties. first, you need to find elements that are found in the same group (groups are vertical in the periodic system), and then to see whether they have the same valence number. if they meet these criteria, they will have similar properties.

the first pair: ne (neon) and kr (krypton), are noble gases found in group 8

the second pair: li (lithium) and k (potassium), found in group 1

the third pair: s (sulfur) and te (tellurium), found in group 6