Question

What is the decreasing order of strength of the bases?
$OH^{-}, \, NH_{2}^{-},H-C\equiv C^{-}$ and $CH_{3}-CH_{2}^{-}$ ?

• A. $CH_{3}-CH_{2}^{-}>NH_{2}^{-}>H-C\equiv C^{-}>OH^{-}$
• B. $H-C\equiv C^{-}>CH_{3}-CH_{2}^{-}>NH_{2}^{-}>OH^{-}$
• C. $OH^{-}>NH_{2}^{-}>H-C\equiv C^{-}>CH_{3}-CH_{2}^{-}$
• D. $NH_{2}^{-}>H-C\equiv C^{-}>OH^{-}>CH_{3}-CH_{2}^{-}$

Answer 1

Answer: (A)

As the strength of conjugate base $\alpha $ 1/acidic strength
As acidic strength is
$\text{HOH}>\text{HC}\equiv \text{CH}>\text{N}\text{H}_{3}>\text{C}\text{H}_{3}-\text{C}\text{H}_{3}$
So $\text{C}\text{H}_{3}-\text{C}\text{H}_{2}^{-}>\text{N}\text{H}_{2}^{-}>H-C\equiv C^{-}>\text{O}\text{H}^{-}$