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JEE Main 202127 AugustEvening Shift
Exam
JEE Main
Year
2021
Date
27 August
Shift
Evening Shift
Subject
Chemistry
Chapter
Thermodynamics (C)

JEE Main 2021 · 27 August · Evening Shift · Chemistry · Thermodynamics (C)

Data given for the following reaction is as follows : FeO _ ( s ) +...

Data given for the following reaction is as follows :

FeO(s)+C(graphite)⟶Fe(s)+CO(g){FeO}_{( s )} + {C}_{( graphite )} ⟶ {Fe}_{( s )} + {CO}_{( g )}

Substance ΔfH°(kJmol−1){\Delta}_{f}H ° \left({kJmol}^{- 1}\right) \DeltaS°(Jmol−1K−1)\DeltaS ° \left({Jmol}^{- 1}{K}^{- 1}\right)
FeO(s){FeO}_{( s )} −266.3- 266 . 3 57.4957 . 49
C(graphite){C}_{( graphite )} 00 5.745 . 74
Fe(s){Fe}_{( s )} 00 27.2827 . 28
CO(g){CO}_{( g )} −110.5- 110 . 5 197.6197 . 6

The minimum temperature in KK at which the reaction becomes spontaneous is_____.(Integer answer)

Correct answer

0

Step-by-step solution

{T}_\min = \left(\dfrac{\Delta ° H}{\Delta ° S}\right)

ΔoHrxn=[Δf°H(Fe(s))+Δf°H(CO(g))]−[Δf°H(FeO(s))+Δf°H(C(graphite))]{\Delta}^{o}{H}_{rxn} = \left[{\Delta}_{f}^{°}H ( {Fe}_{\left(s\right)} ) + {\Delta}_{f}^{°}H ( {CO}_{\left(g\right)} )\right] - \left[{\Delta}_{f}^{°}H ( {FeO}_{\left(s\right)} ) + {\Delta}_{f}^{°}H ( {C}_{\left(graphite\right)} )\right]

=[0−110.5]−[−266.3+0]= [ 0 - 110 . 5 ] - [ - 266 . 3 + 0 ]

=155.8kJ/mol= 155 . 8kJ / mol

Δ°Srxn=[Δ°S(Fe(s))+Δ°S(CO(g))]−[Δ°S(FeO(s))+Δ°S(C(graphite))]\Delta ° {S}_{rxn} = \left[\Delta ° S ( {Fe}_{\left(s\right)} ) + \Delta ° S ( {CO}_{\left(g\right)} )\right] - \left[\Delta ° S ( {FeO}_{\left(s\right)} ) + \Delta ° S\left({C}_{( graphite )}\right)\right]

=[27.28+197.6]−[57.49+5.74]= [ 27 . 28 + 197 . 6 ] - [ 57 . 49 + 5 . 74 ]

=161.65J/mol.K= 161 . 65J / mol . K

{T}_\min = \dfrac{155 . 8 \times {10}^{3}J / mol}{161 . 65J / mol - K} = 963 . 8K

≈964K\approx 964K (nearest integer)

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