Question

in which structure carbon does not act as a electrophile​

Answer 1

Among the given, H3O+ has lone pair of electrons for donation, thus it is not electron-deficient and hence, does not behave like an electrophile.

Answer 2

Carbon does not act as an electrophile​ in methyl cyanide, hydronium ion structure.

Explanation:

• Electrophiles are those electron-deficient species that are attracted to electron-rich centers and which have one lone pair of electrons for donation.
• After the donation, it will form a bond.
• They are electron deficient with positive charges.
•  $CH_{3}CN and H_{3}O^{+}$ has lone pair of electrons for donation, thus it is not electron-deficient and hence, does not behave like an electrophile.
• They can also be termed electron-loving species.