Which of the following is not an electrophile?

The correct answer is option 1.

Key Points

• Electrophiles are species that seek electrons and can accept an electron pair. They are electron-deficient and usually have a positive charge or an incomplete octet.
• Na⁺ (Sodium ion) is a cation, but it is not an electrophile because it does not have an empty orbital to accept electrons. Instead, it is a positively charged spectator ion and does not actively participate in electrophilic reactions. Hence, option 1 is correct.
• BF₃ (Boron trifluoride) is an electrophile because boron has an incomplete octet and can accept electron pairs.
• H⁺ (Proton) is a strong electrophile as it has no electrons and readily accepts electron pairs.