why are primary alcohols more acidic then secondary & tertiary alcohols?

Dear Student

The acidic character of alcohols is due to the polar nature of O–H bond. An electron-releasing group increases electron density on oxygen tending to decrease the polarity of O-H bond.

The number of electron-releasing groups decreases in the order tertiary alcohol > secondary alcohol >primary alcohol

Thus the acidic strength decreases in the  order:

CH₃CH₂OH > (CH₃)₂CHOH  > (CH₃)₃COH

(Primary)  (Secondary)  (Tertiary)   

Hope this clears your confusion