AP EAMCET202017 Sep 2020Morning ShiftChemistryHydrocarbonsActual
Decreasing order of acidity of the following terminal acetylenes is
Options
- A(i) (> ) (iii) (> ) (ii) (> ) (iv)
- B(i) (> ) (ii) (> ) (iv) (> ) (iii)
- C(i) (> ) (iv) (> ) (ii) (> ) (iii)
- D(i) (> ) (iii) (> ) (iv) (> ) (ii)
Correct answer
B. (i) (> ) (ii) (> ) (iv) (> ) (iii)
Step-by-step solution
Let us consider the structure of respective conjugate bases (carbonions), EWG ((-R) ) stabilise carbanions but EDG ((+R > +I) ) destabilise carbanions. [EWG : Electron withdrawing group EDG : Electron donating group] A stronger acid produces stable conjugate base. So, the order of acidity will be ( (i) > (ii) > (iv) > (iii) )