Which of the following substituents will increase the acidity of a substituted benzoic acid (relative to the acidity of benzoic acid)?Select answer from the options belowNitroHydroxyl MethylMethoxy

The acidity of a substituted benzoic acid is increased by electron-withdrawing groups, which stabilize the negative charge on the carboxylate ion formed after deprotonation.

1. Nitro (-NO2) group: This is a strong electron-withdrawing group. It pulls electron density away from the benzene ring and stabilizes the negative charge on the carboxylate ion. Therefore, it increases the acidity of the benzoic acid.

2. Hydroxyl (-OH) group: This group can donate a hydrogen bond to the carboxylate ion, stabilizing it and thus increasing the acidity of the benzoic acid.

3. Methyl (-CH3) group: This is an electron-donating group. It pushes electron density towards the benzene ring and destabilizes the negative charge on the carboxylate ion. Therefore, it decreases the acidity of the benzoic acid.

4. Methoxy (-OCH3) group: This is also an electron-donating group. It destabilizes the negative charge on the carboxylate ion and thus decreases the acidity of the benzoic acid.

So, the substituents that will increase the acidity of a substituted benzoic acid are the Nitro and Hydroxyl groups.