I have to perform lab once a week, yesterday, Mam assigned us to synthesize fluorescein from resorcinol and phthalic anhydride. In the last lecture (before the performance) Mam explained the procedure, how to handle samples, amount of chemicals and the method of its preparation.

We entered the lab and wear lab coats and gloves, we are actually to boys me and my friends in strength of 22-girls who are studying organic chemistry.

The student who performed previous lab, didn't wash the apparatus, firstly we washed the apparatus, which includes, beaker, conical flask, funnel, round bottom flask, spatula and a measuring cylinder of 10 ml, to measure the exact volume of the sample solutions.

Then the issue was chemicals, which are in form of crystals and we needed in powdered form for performing the experiment. I asked the lab attendant for a grinder to grind crystals, but no grinder is available in the lab, he give us old mortar & pestle to convert crystals into powder. I bring and wash it for further use.

A student weighed 3.5 grams of resorcinol crystals and I converted these crystals into powdered form using mortar and pestle, same way grinded 2.5 grams of phthalic after weighing from the electronic measuring balance.

Next step was the preparation of oil bath, using paraphenol, we prepared an oil bath in a beaker. Put it on the hot plate. Then mix both resorcinol and phthalic anhydride in a florence flask, placed it on the oil bath and allow it to heat between 140-180° temperature.

In next step we heated Zinc chloride which will use as a catalyst for fluorescein synthesis from phthalic anhydride and resorcinol.

Weighed 2.5 grams of zinc chloride and put in a petri dish, heated it, so it can melt using the bunsen burner and tripod stand.

After melting Zinc chloride, drop it in a florence flask which is placed on the hot plate for heating after different internals.

A further step is to prepare 10% HCl solution volume should be 40ml, so using the measuring cylinder measured 36ml of water added in the beaker of 50 ml, then measured the 4ml of hydrochloric acid and pour in the same beaker, solution prepared.

Allowed the temperature of florence flask to drop till 90°, then added chloride with constants stirring after different intervals. premature crystals are start forming. But within seconds sample sticked with the wall.

Again we heated it and using the filter paper filtered out crytals. The real method is to filter out when sample solution become cool, but because of sticky property we filtered out early. And finally obtained these crystals.

3.9 grams of flourescein is prepared. The next step was to calculate out yield, which can be done after the lab. This was our last lab before the mid-term exams,

See you soon guys after exams!