Suggest structures for the compounds J to K and explain your reasoning in each case.
A neutral liquid I, C8H6O2, gave J upon heating with dilute hydrochloric acid. 1 mole of J reacted with 2 moles of PCl5 to form K, C8H6Cl2O, and gave white fumes. K gave a strongly acidic solution in water and yielded J upon heating with aqueous NaOH followed by acidification.
非常感谢！
这是我儿子的解释。也不知答案正不正确。儿子画了几幅图，请参考添加的附件。
C : H ratio is very high. Therefore, you can guess that there is a benzene ring inside.
K is strongly acidic -> K has an acyl chloride group. That is the only organic chemical we know that is strongly acidic.
From there, you can easily guess the structure of of K. However, you are not sure of the position of the acid group and the alkyl group with respective to each other.
1 mole of J reacts with 2 moles of PCl5 -> This means that two halide substitutions took place to form K. One substition is done on the acid group and the other on the alkyl group. Remember that PCl5 changes the -OH group to the -Cl group. From there, you can get J.
Getting I is the hardest part. Notice that the acid group already has 2 oxygen atoms, and that the number of hydrogen atoms in the whole molecule is surprisingly small. Therefore, we can guess that there is an ester bond in the structure. If there is an ester bond, then the acid and alkyl group must be next to each other. From there, you can get the whole structure.
非常感谢您和您的儿子。我会将答案给我亲戚家的孩子参考。