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प्रश्न
Consider the following reaction between zinc and oxygen and choose the correct options out of the options given below:
\[\ce{2 Zn (s) + O2 (g) -> 2 ZnO (s); ∆H = - 693.8 kJ mol^{-1}}\]
(i) The enthalpy of two moles of \[\ce{ZnO}\] is less than the total enthalpy of two moles of \[\ce{Zn}\] and one mole of oxygen by 693.8 kJ.
(ii) The enthalpy of two moles of \[\ce{ZnO}\] is more than the total enthalpy of two moles of \[\ce{Zn}\] and one mole of oxygen by 693.8 kJ.
(iii) 693.8 kJ mol–1 energy is evolved in the reaction.
(iv) 693.8 kJ mol–1 energy is absorbed in the reaction.
उत्तर
(i) The enthalpy of two moles of \[\ce{ZnO}\] is less than the total enthalpy of two moles of \[\ce{Zn}\] and one mole of oxygen by 693.8 kJ.
(iii) 693.8 kJ mol–1 energy is evolved in the reaction.
Explanation:
As we know from thermodynamics,
`Δ_rH^o` = `isuma_iΔ_fH^⊙` (products) - `suma_ib_iΔ_fH^⊙` (reactants)
Since, the above reaction is an exothermic reaction, the enthalpy of reactant is more than the enthalpy of product.
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