Consider the following data : ( methane, g ) = - X kJ mol - 1 Enthalpy of sublimation of graphite = Y kJ mol - 1 Dissociation enthalpy of H 2 = Z kJ mol - 1 The bond enthalpy of C–H bond is given by : [2026]

Question

Consider the following data :

$Δ_{f} H^{⊝} (methane, g) = - X {kJ mol}^{- 1}$

$Enthalpy of sublimation of graphite = Y {kJ mol}^{- 1}$

$Dissociation enthalpy of H_{2} = Z {kJ mol}^{- 1}$

The bond enthalpy of C–H bond is given by : [2026]

Smart Achievers · Accepted Answer

(1)

$C (s) + 2 H_{2} (g) \to {CH}_{4} (g)$

$- x = (Δ H_{sub} of carbon) + 2 \times (B.E. of H-H)$

$- 4 \times (B.E. of C-H)$

$- x = y + 2 z - 4 (B.E. of C-H)$

$B.E. of C-H = \frac{y + 2 z + x}{4}$

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