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One mole of methane, CH₄, reacts with one mole of halogen, X₂ - VCE - SSCE Chemistry - Question 29 - 2022 - Paper 1
Question 29
One mole of methane, CH₄, reacts with one mole of halogen, X₂. X can be fluorine, F, chlorine, Cl, or bromine, Br. The general equation for the reaction is given bel... show full transcript
Worked Solution & Example Answer:One mole of methane, CH₄, reacts with one mole of halogen, X₂ - VCE - SSCE Chemistry - Question 29 - 2022 - Paper 1
Step 1
A. The strength of the bonds from weakest to strongest is C−Br < C−Cl < C−F.
Answer
The statement is incorrect. The correct order of bond strength for these bonds is C−F > C−Cl > C−Br, meaning that the C−F bond is the strongest due to the smaller atomic size and the greater effective overlap between the carbon and fluorine atoms.
Step 2
B. Since hydrogen has the smallest atomic radius, the C−H bond is the weakest bond.
Answer
This statement is misleading. While hydrogen does have a small atomic radius, bond strength is determined by factors such as electronegativity and orbital overlap. The C−H bond is actually stronger than the C−Br bond.
Step 3
Step 4
D. The C−Br, C−Cl, and C−F bonds are equal in strength because Br, Cl, and F are halogens.
Answer
This statement is also incorrect. Although bromine, chlorine, and fluorine are all halogens, their bond strengths differ due to the varying atomic sizes and electronegativities. The strength increases from C−Br to C−Cl to C−F.