A Level Chemistry OCR Practice Exam

What happens during an elimination reaction?

1. A saturated molecule becomes an unsaturated molecule

2. A compound is formed from its constituent elements

3. An electrophile accepts electrons

4. A molecule is completely decomposed

The correct answer is: A saturated molecule becomes an unsaturated molecule

During an elimination reaction, a saturated molecule indeed becomes an unsaturated molecule. This transformation occurs when bonds in the molecule break, typically resulting in the formation of a double or triple bond. The reaction involves the removal of small molecules, such as water or hydrogen halide, from the larger molecule. An example of this is the dehydration of alcohols to form alkenes, where the alcohol loses a water molecule, resulting in a carbon-carbon double bond. The other options do not accurately describe the process of an elimination reaction. For instance, forming a compound from its constituent elements refers to a synthesis reaction, while an electrophile accepting electrons is characteristic of electrophilic reactions rather than eliminations. Lastly, complete decomposition of a molecule describes a different type of reaction where a single compound breaks down into simpler products. Thus, the correct understanding involves recognizing that elimination primarily concerns the transition from saturation to unsaturation.