What is the major side product for the grignard reaction between phenyl magnesiu

Question

What is the major side product for the grignard reaction between phenyl magnesium bromide and benzophenone? a) triphenylmethanol b) water c) biphenyl d) there is no major side product, they are all equally irritating When you are working up the intermediate anion in the reaction, you need to check the acidity of the aqueous solution. Why is this? a) You have to make sure that the ether layer is acidic b) the anion needs to be protonated in order to form the alcohol product c)You always add an acid when you're working up a reaction d) none of the above How can the major impurity be removed from the mixture? a) The alcohol product is soluble in ligroin and the impurity is not b) The alcohol product is not soluble in ligroin and the impurity is soluble in ligroin c) The impurity forms a solid upon the addition of the acid in the workup step d) There wasn't any major impurity to remove If you wanted to make toluene from para-bromo toluene, how could you do so using a grignard reaction? a) Add sodium, then water b) Add sodium, then toluene will form as a byproduct c) You cannot make toluene from para-bromo toluene d) It just happens

Explanation / Answer

Solution 1

PhMgBr + Benzophenone ------> Triphenymethanol ( Major) '

Solution 2  Option- B

Explanation - Because many Grignard reactions yield an alkoxide, which can be protonated with dilute acid (protonating the water, which then transfers its proton to the alkoxide) to form an unreactive alcohol, while the remaining water deactivates the Grignard reagent.

Solution 3 Option B

Explanation - Ligroin is a mixture of hydrocarbons, so is very nonpolar and will readily dissolve the nonpolar biphenyl impurity. The desired triphenylmethanol product is not very soluble in ligroin and hopefully remains as a solid.

Solution 4 Option A

Add sodium + then water

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