Question

The correct order of increasing basicity of the given conjugated bases is:

• A. $RCO{O}^{-}<HC\equiv C^{-}<N{H}_2^{-}<R^{-}$
• B. $RCO{O}^{-}<HC\equiv C^{-}<R^{-}<N{H}_2^{-}$
• C. $R^{-}<HC\equiv C^{-}<RCO{O}^{-}<N{H}_2^{-}$
• D. $RCO{O}^{-}<N{H}_2^{-}<HC\equiv C^{-}<R^{-}$

Answer 1

The correct option is A $RCO{O}^{-}<HC\equiv C^{-}<N{H}_2^{-}<R^{-}$

As we move from left to right, basicity of the anion decreases due to the increase in effective nuclear charge. So, the basicity of $R^{-}$ is highest.
However, amide is more basic than acetylide because $sp$ carbon is more elecronegative.
In case of $RCO{O}^{-}$ the negative charge is in conjugation. So, the basicity is least.
Hence, the correct order is A