Question

what is the order of ka of following compounds

Answer 1

Answer:

Weaker acids have higher pK  

a  

−

 

​  

−OCH  

3

​  

 at meta-position exerts only −I effect, hence increases the acidity.

−I effect order: −NO  

2

​  

>−OCH  

3

​  

>−Cl

−CH  

3

​  

 has +I effect.

pKa is inversely proportional to acidity.

So, option A is correct.