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Which equation represents a valid propagation step in the chlorination of ethane? A C₂H₆ + Cl• → C₂H₅Cl + H• B C₂H₅Cl + Cl• → C₂H₄Cl₂ + HCl C C₂H₅Cl + H• → C₂H₆ + HCl D C₂H₆ + Cl• → C₂H₅Cl - CIE - A-Level Chemistry - Question 21 - 2018 - Paper 1
Question 21
Which equation represents a valid propagation step in the chlorination of ethane? A C₂H₆ + Cl• → C₂H₅Cl + H• B C₂H₅Cl + Cl• → C₂H₄Cl₂ + HCl C C₂H₅Cl + H• → C₂H₆ + HC... show full transcript
Worked Solution & Example Answer:Which equation represents a valid propagation step in the chlorination of ethane? A C₂H₆ + Cl• → C₂H₅Cl + H• B C₂H₅Cl + Cl• → C₂H₄Cl₂ + HCl C C₂H₅Cl + H• → C₂H₆ + HCl D C₂H₆ + Cl• → C₂H₅Cl - CIE - A-Level Chemistry - Question 21 - 2018 - Paper 1
Step 1
C C₂H₅Cl + H• → C₂H₆ + HCl
Answer
This reaction depicts a valid propagation step because it involves the interaction between an alkyl radical (C₂H₅•) and a hydrogen radical (H•). During this process, the alkyl radical effectively captures the hydrogen atom, forming ethane (C₂H₆) and releasing HCl as a product. This is consistent with the notion of radical chain reactions in halogenation, where radicals react to produce new radicals.
Step 2
B C₂H₅Cl + Cl• → C₂H₄Cl₂ + HCl
Answer
This equation represents a valid propagation step because it shows the chlorination of ethane involving a chlorine radical (Cl•) reacting with ethyl chloride (C₂H₅Cl). In this step, new products are created: dichloroethane (C₂H₄Cl₂) and hydrogen chloride (HCl). The presence of a chlorine radical initiates the reaction, thus, it is a true propagation step.