Chemistry Question (Melting point)

[fuhgidabowdit]

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Assume that your product has a melting point of 187-190 degrees Celsius. Even though this value does not match any of the isomers, you could still reasonably state which chlorotoluene you started with. Explain

These are the values for the chlorotoluenes:

BOILING.POINT. MELTING.POINT.
2-chlorotoluene 157-159 138-140
3-chlorotoluene 160-162 155-157
4-chlorotoluene 162-164 239-241

 

[Toolmatica]

This answer is to the way you wrote your question:

I would think that you would have to assume that your product is unpure. MP is colligative and the presence of impurities would decrease your melting point. I can't think of anything off the top of my head that would increase the melting point. For this reason I would assume that it's 4-chlorotoluene. In order to be any of the others it would require an increase in melting point. Hope that helps.

However, I dont understand how melting point would be at a higher temperature than a boiling point and your values don't match what's written on wikipedia for the properties of the compounds you're talking about.

 

[fuhgidabowdit]

Thanks, your right though, the melting point values were for chlorobenzoic acid which would be the product of chlorotoluene. Your answer makes sense, impurities couldnt increase the melting point values of the pure product (only decrease)