Final answer:
Methane (CH4) would have the slowest reaction rate with Cl2 and light compared to Ethane, Propane, and Butane due to its simplicity and fewer hydrogen atoms available for substitution, resulting in fewer possible reaction sites.
Step-by-step explanation:
The student asked which of the following alkanes has the slowest reaction rate with Cl2 and light: Methane, Ethane, Propane, or Butane. When considering the reactivity of alkanes with halogens like chlorine in the presence of light, it's important to note that the reaction rate generally increases with the complexity of the alkane structure. This is because more complex alkanes have greater numbers of hydrogen atoms that can be substituted by a halogen atom, thus increasing the number of potential reaction sites.
Methane (CH4) is the simplest alkane with only four hydrogen atoms available for substitution, making it less reactive than its more complex counterparts. Ethane (C2H6) and Propane (C3H8) have more hydrogen atoms that can be substituted. Butane, which is not specifically mentioned in the supporting information but follows the trend, is a bigger molecule with even more hydrogen atoms available than propane. Hence, out of the options provided, Methane (A) would have the slowest reaction rate with Cl2 and light because it has the smallest number of hydrogen atoms and is the least complex molecule.