Question

How do we order the following considering their acidic nature?

1)CH3COOH
2)Phenol
3)C6H5COOH
4)CH3C(triple bond)CH
5)a cyclic alcohol [ (CH2)5-CH-OH ]

I know that Phenol is acidic than alcohols and Carboxylic acids are acidic than alcohols and the alpha H in the third compound is less acidic than alcohols and even (water?)

Answer 1

1,2,3 you can tell by looking up the Ka for each.
The end (right end) H is acidic in 4 and alcohols are the lowest (if acidic at all).

You can find tables that list pKa values for each class. pKa is the way to go.

Answer 2

But we are asked to order them without giving the ka values?

Answer 3

CH3C---H<alcohol<phenol<CH3COOH<benzoic acid