STANDARD Physics Enthalpy MCQ Question
Consider the reactions given below. On the basis of these reactions find out which of the algebraic relations given in options (a) to (d) is correct? (i) C_(g) + 4H_(g) → CH₄(g); Δ_rH = x kJ mol⁻¹ (ii) C_(graphite, s) + 2H₂(g) → CH₄(g); Δ_rH = y kJ mol⁻¹
x = y
x = 2y
x > y
x < y
Correct Answer
Detailed Explanation
In eqn. (i), no bond is being broken while in eqn. (ii), H–H bonds are broken. So, in eqn. (ii) some of the energy is used up to break the bonds. Thus, x > y.
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