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QJEEM21Ch81c3: JEE Main 2021 Chemistry - Class 11 JEEM21Ch81c3 Solution: The average S-F bond energy in kJ mol 1 of SF 6 is…

The average S-F bond energy in kJ mol −- 1 of SF6 is _____________. (Rounded off to the nearest integer)

[Given : The values of standard enthalpy of formation of SF6(g), S(g) and F(g) are - 1100, 275 and 80 kJ mol −- 1 respectively.]

Step-by-Step Verified Solution

JEE Main 2021 (Online) 26th February Evening Shift Chemistry - Thermodynamics Question 105 English Explanation
So, ΔfH∘[S,g]+6×ΔfH∘[F,g]=ΔfH∘[SF6,g]\Delta_f H^{\circ}[S, g]+6 \times \Delta_f H^{\circ}[F, g]=\Delta_f H^{\circ}\left[SF_6, g\right] +6×ES−F+ 6 \times E_{S-F}

[∴ES−F=\left[\therefore E_{S-F}=\right. Average S−FS-\mathrm{F} bond energy in SF6]\left.\mathrm{SF}_6\right]

275+6×80=−1100+6×ES−F275+6 \times 80=-1100+6 \times E_{S-F}

⇒ES−F=275+6×80+11006\Rightarrow E_{S-F}=\frac{275+6 \times 80+1100}{6} =309.16 kJ mol−1=309 kJ mol m−1=309.16 \mathrm{~kJ} \mathrm{~mol}^{-1}=309 \mathrm{~kJ} \mathrm{~mol} \mathrm{~m}^{-1}

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