A Level Chemistry OCR Practice Exam

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Prepare for the A Level Chemistry OCR Exam with quizzes. Study with flashcards, multiple choice questions, hints, and explanations. Enhance your understanding and boost your confidence for success!

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What is a carbanion?

An organic ion with a positive charge
An organic ion in which a carbon atom has a negative charge
A neutral organic molecule
An ion with a charge derived from oxygen

The correct answer is: An organic ion in which a carbon atom has a negative charge

A carbanion is indeed defined as an organic ion where a carbon atom carries a negative charge. This negatively charged species forms when a carbon atom has more electrons than usual, typically resulting from the addition of an electron or the removal of a proton from a carbon-hydrogen bond. Carbanions play an essential role in various organic reactions, particularly in nucleophilic reactions, where the negatively charged carbon atom acts as a strong nucleophile. The structure and stability of carbanions can vary significantly depending on their environment, such as the presence of electron-withdrawing or electron-donating groups. In contrast, an organic ion carrying a positive charge represents a different type of ion known as a carbocation, not a carbanion. A neutral organic molecule does not carry any charge, while ions derived from oxygen would refer to oxyanions—not carbanions. Therefore, B accurately captures the essence of what a carbanion is.