Question

Use thye given data to calculate the resonance energy of $N_{2}O$. $(\Delta H_f{}^o$ of $N_{2}O=82kJmo{l}^{-1})$ , Bond energies of NΞN, N=N,O=O and N=O bonds are 946 ,418 ,498 and 607 kj mol-1 respectively.
Choose the correct option.

• A. 88kJ $mo{l}^{-1}$
• B. 77kJ $mo{l}^{-1}$
• C. -88kJ$mo{l}^{-1}$
• D. -77kJ$mo{l}^{-1}$

Answer 1

The correct option is C -88kJ$mo{l}^{-1}$

The options given are actually part of data of que--

SO using them

The equation for the formation of one mole of N₂O will be

NΞN (g) + ½ O=O (g) ---> N=N=O

Calculating the value of Δ_fH⁰ for this reaction will be Δ_fH⁰ = [B.E.(NΞN) + ½ B.E.(O=O)] – [B.E.(N=N) + B.E.(N=O)]

=[946 + ½ (498)] – [418 + 607] kj mol-1 = 170kj mol^-1

Resonance energy = Observed Δ_fH⁰ – Calculated Δ_fH⁰ = 82 – 170 = - 88 kj mol^-1

^{SO the answer is =Resonance energy =-88}