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13 Dec 2019

A ketone and a Grignard reagent react in ether solution followed by acid workup, to form a tertiary alcohol. Grignard reactions must be scrupulously dry in order to work effectively. A common method of drying glassware is to rinse with acetone prior to use. Why is rinsing with acetone not suitable for the reaction stated in the question.

a)Magnesium does not dissolve in acetone.

b)Water dissolves in acetone. Adding acetone will add water to the reaction flask.

c)Magnesium dissolves in acetone. Adding acetone will remove a vital reactant from the flask.

d)Acetone is a ketone. Grignard reagents will react with acetone to make an unwanted byproduct.

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22 Mar 2023

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In the synthesis of a diester experiment (Chemiluminescence) using 4-nitrophenol (procedure shown below), explain the significance / role of the reagents used:

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Please consider the preperation of benzoic acid: a Grignard Reaction.

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QUESTION:

Procedure:

* add 1.2g of magnesium and 3 crystals of iodine to RB flask and immediately assemble the dry water condenser and drying tube containing cotton and anhydrous calcium chloride to RB flask

*then add 5.2 mL bromobenzene to 5 mL of diethyl ether to seperatory funnel and turn on condenser

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*maintain the vigorousness of the reaciton by continuously adding 3.5 mL portions of diluted bromobenzene-ether mixture every 30 seconds

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* drain the lower aqueous layer into a large beaker and slowly acidify using concentrated 12M HCl (aq). Stir the mixture and add HCl (aq) until pH is about 1-2 pH units.

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The absorbance using UV spectrometer is =1.75

Please help within the following

Using the reported value of the extinction coefficient of 112,000 M^-1 cm^-1, calculate the concentration of diluted sample and (according for dilution ) estimate the percent yield of this reaction by determining the number of moles of the dye formed. You can assume that the dye follows the Beer-Lambert Law and that A=ebc which for a 1cm cell simplifies to Absorbance A= ( 112,000 M^-1 cm^-1)(1.00cm) (concentration of crystal violet).

Please help thank you!