1. A student performs the following steps to isolate biphenyl from a solid 1:1 m
ID: 535530 • Letter: 1
Question
1. A student performs the following steps to isolate biphenyl from a solid 1:1 mixture of biphenyl and salicylic acid. a. Dissolve 2.0 grams of the mixture in 20 mL of ether b. Extract the ether layer 2-3 times with an aqueous solution of 5% sodium bicarbonate c. Add 2-3 spatula tips of sodium sulfate to the ether layer d. Extract the ether layer with a saturated aqueous solution of sodium chloride. e. Isolate the organic layer and evaporate the ether. The solid they collect at the end weighs 1.23 g and has a wide melting point range. If the student expected to recover 1 gram of pure biphenyl, explain, based on the procedural information given above, why this student did not see their expected results.
Explanation / Answer
Actualy when the student is extracting pure biphenyl from solid 1:1 mixture of biphenyl salicyclic acid, there might be some impurities added in the purified solid which he collects,yet he extract the aqueous layes 2 3 times with NaHCO3 but still there might be extra impurities added whether it may be from surroundings or we can say it is an skill or instrumental error, an error ehich arises because of handling the intrument like while filtering etc.
due to addition of impurities the yield is little bit high and also impurities raises the melting point due to we got a wide range of melting point as pure biphenyl melts exactly at 69.2 degree celsius
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