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NEET 2020
Exam
NEET
Year
2020
Subject
Chemistry
Chapter
Thermodynamics (C)

NEET 2020 · Chemistry · Thermodynamics (C)

At standard conditions, if the change in the enthalpy for the...

At standard conditions, if the change in the enthalpy for the following reaction is −109kJmol−1- 109{kJmol}^{- 1}

H2(g)+Br2(g)→2HBr(g){H}_{2 ( g )} + {Br}_{2 ( g )} \to 2{HBr}_{( g )}

Given that bond energy of H2{H}_{2} and Br2{Br}_{2} is 435kJmol−1435{kJmol}^{- 1} and 192kJmol−1192{kJmol}^{- 1}, respectively, what is the bond energy (in kJmol−1kJ{mol}^{- 1})ofHBr?of HBr ?

Options

  1. A368368
  2. B736736
  3. C518518
  4. D259259

Correct answer

A. 368368

Step-by-step solution

\DeltaH=Σ(B⋅E)Reactants−Σ(B.E)Products\DeltaH = Σ ( B \cdot E{)}_{\text{Reactants}} - Σ ( B . E{)}_{\text{Products}}
−109=[B⋅E(H−H)+B⋅E(Br−Br)]−[2×B⋅E(H−Br)]- 109 = \left[B \cdot {E}_{( H - H )} + B \cdot {E}_{( Br - Br )}\right] - \left[2 \times B \cdot {E}_{( H - Br )}\right]
−109=435+192−2×B⋅E(H−Br)- 109 = 435 + 192 - 2 \times B \cdot {E}_{( H - Br )}
B.E(H−Br)=435+192+1092=368KJ/molB . {E}_{( H - Br )} = \dfrac{435 + 192 + 109}{2} = 368KJ / mol
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