A student bubbles ethene gas into bromine water - OCR Gateway - GCSE Chemistry - Question 11 - 2019 - Paper 4

When ethene (C2H4) reacts with bromine water (Br2), an addition reaction occurs. In this reaction, the double bond of ethene opens up to form a dibrominated compound. The correct product will have bromine atoms added to each of the two carbon atoms of the original double bond.

Looking at the options:

• Option A shows the original double bond structure with bromine atoms added correctly but does not represent the product with the double bond broken.
• Option B displays a structure with the double bond broken and two bromine atoms added to the carbons, therefore representing the product of the reaction accurately.
• Option C does not show the bromine addition correctly since one carbon does not have both bromine atoms.
• Option D again does not represent the expected product since it has an extra bromine with an incomplete bonding on one carbon.

Thus, the correct answer is B, which accurately depicts the final product formed after the bromination of ethene.