On reaction with acid,$4$-pyrone gives a very stable cationic product. Which of the following structures shows the protonation site in that product?

Which of the following has the highest nucleophilicity?

Which of the following species is not electrophilic in nature?

The indicated atom is not a nucleophilic site in

The cyanide ion $(CN^-)$ acts as an ambident nucleophile. From which end does it act as a stronger nucleophile in an aqueous medium? Give a reason for your answer.

Which of the following statements is true?