Question

Which compound(s) can protonate NH3? A : CH3CO2H (pKa = 4.75) B : CH3CH3 (pKa = 50) C : NH3 (pKa = 38)

Answer 1

Compound A (CH3CO2H) and Compound C (NH3) can protonate NH3, while Compound B (CH3CH3) cannot.

Step-by-step explanation:

In this question, we are asked to identify which compound(s) can protonate NH3. Protonation refers to the process of adding a proton (H+) to a molecule or ion. A compound with a lower pKa value will be a stronger acid, meaning it is more likely to donate a proton. Based on the information given, we can determine that compound A (CH3CO2H) and compound C (NH3) can protonate NH3, while compound B (CH3CH3) cannot. This is because compound A has a pKa value of 4.75, which is lower than the pKa value of NH3 (38), and it therefore has a greater tendency to donate a proton. Compound B, on the other hand, has a pKa value of 50, indicating that it is a very weak acid and unlikely to donate a proton.

Answer 2

Protonation means addition of proton to a compound. Protonation of NH₃ can take place if any acidic compound releases proton (H⁺ ion) easily. The acid which can be dissociated easily can donate proton to other compound. Whether the removal of proton is possible or not can be understood from its dissociation constant value (Kₐ). If Kₐ value is more dissociation of the compound is easy means H⁺ ion can be removed easily. Also, if Kₐ value is inversely related to
`p^{k_(a) }` value. If
`p^{k_(a) }` value is less, then kₐ value is more which indicates dissociation is also more, donation of proton is also easy. As per given information,
`p^{k_(a)` value of CH₃COOH is less as compared to CH₃CH₃ and NH₃. So, CH₃COOH can protonate NH₃.