Use bromine water to test for unsaturation.

In the subtopic Structure, bonding and reactivity, this AQA A-Level Chemistry 7405 learning objective focuses on use bromine water to test for unsaturation. It belongs to Alkenes, so revision should stay anchored to this exact subtopic rather than drifting into a generic GCSE-level chemistry summary. Approved keywords to use include bromine, water, test, unsaturation. Bromine water. means a solution of bromine in water used to test for unsaturation in organic compounds Avoid the mistake of students often incorrectly state that bromine water changes color when it comes into contact with alkenes without mentioning the role of unsaturation; instead, to correctly explain the test for unsaturation, state the formula: Bromine water (Br2) reacts with unsaturated compounds (alkenes) to form colorless dibromo compounds. Substitution: When bromine water is added to an alkene, the C=C double bond reacts with Br2. Working: The reaction leads to the decolorization of bromine water, indicating the presence of unsaturation. Answer: The bromine water will turn from brown to colorless, confirming unsaturation. Units/Conclusion: The test confirms the presence of a C=C double bond in the alkene For exam answers, to test for unsaturation in alkenes, add bromine water to the sample. If the solution turns from brown to colourless, it indicates the presence of a C=C double bond