Q9-9P c - Organic Chemistry (Mcmurry)

Question

The pk_a of acetone, $\mathit{C}{\mathit{H}}_{\mathbf{3}}\mathit{C}\mathit{O}\mathit{C}{\mathit{H}}_{\mathbf{3}}$, is 19.3. Which of the following bases is strong enough to deprotonate acetone?

(c) $\mathit{N}\mathit{a}\mathit{H}\mathit{C}{\mathit{O}}_{\mathbf{3}}$($\mathit{p}{\mathit{k}}_{\mathbf{a}}$of H₂CO₃ 6.4)

Step-by-Step Solution

Answer

Answer:

Not strong enough to deprotonate acetone due to less pk_a then acetone.

Step1: pk a of acetone

pk_a is a number that describes the acidity of the molecule. Lower the value of pk_a stronger will be acidic and easily donate a proton and higher the value of pk_a weaker will be the acid and stronger will be the conjugate base.

 Acetone has high value of pk_a then NaHCO₃

Step 2: pk a of NaHCO 3

pk_a of NaHCO₃ is less than acetone, so that NaHCO₃ is the strong acid and the weak conjugate base than acetone due to weak conjugate base NaHCO₃ not able to deprotonate the acetone.