Assuming ideal behaviour, the magnitude of log K for the following reaction at 25°C is x × 10^-1. The value of x is ………………… (integer answer)

3HC $\equiv C H_{(g)} ? C_{6} H_{6 (I)}$

[Given : $Δ_{f} G ° (H C \equiv C H)$ = -2.04 × 10⁵J mol^-1 ; $Δ_{f} G ° (C_{6} H_{6}) = - 1.24 \times 1 0^{5} J m o l^{- 1} :$ R = 8.314 JK^-1mol^-1]

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Vishal Baghel | Contributor-Level 10

3 months ago

$3 C H \equiv C H (g) \to C_{6} H_{6} (l)$

$Δ G^{0} = - R T l n K . . . . . . . . . (i)$

$Δ G^{0} = \sum Δ {G^{0}}_{P} - \sum Δ {G^{0}}_{R} . . . . . . . . . . (i i)$

Equating (i) & (ii)

-2.303 RTlogk = 4.88 × 10⁵

$l o g K = \frac{- 4.88 \times 1 0^{5}}{2.303 \times R \times T} = \frac{- 488000}{5705.848} = - 85.52 = - 855 \times 1 0^{- 1}$

So; magnitude of log K = 855 × 10^-1

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