Question

Suppose the reaction between naphthalene and 2-bromo-2-methylpropane did not run to completion, so that the limiting reagents were not consumed. how would the two TLC plates have looked in your first and second run in this case?

A)there wouuld have been two spots in both cases

B)There would have been three spots in both cases

C)There would have been four pots in both cases

D)There would have been no distinct spots but only streaks.

In order for TLC to help you identify which solutes are present in a solution what property of the solutes must be different

A)Molecular weight

B)color

C)elution time

D)Reactivity with naphthalene( which is what we used)

E)Size of Drop on Plate

Answer 1

The answers to the above given problems will be as follows.

In an incomplete reaction of naphthalene and 2-bromo-2-methylpropane, we started with 2 spots (one each for the two starting materials) and we should end up with 3 spots If spots will appear clearly, one for naphthalene, one for the alkyl halide and one for the product. However, since no such option are given in the choice, the correct answer would thus be,

D) there would have been no distinct spots but only streaks.

In the second problem, identifying solutes with TLC is based on its ability to interact with the stationary phase. The solutes which have strong interactions with the staionary phase will elute last, while the solutes with weak interactions will be eluted first. Thus, the correct answer will be,

C) elution time