NEETChemistryp Block Elements (Group 15, 16, 17 & 18)
Why does some external heating often need to be applied to initiate the reaction between dioxygen (O 2 ) and other elements?
Options
- ATo lower the bond dissociation enthalpy of the O-O double bond
- BTo increase the bond dissociation enthalpy of the O-O double bond
- CTo decrease the reactivity of dioxygen
- DTo increase the number of electrons in dioxygen
Correct answer
A. To lower the bond dissociation enthalpy of the O-O double bond
Step-by-step solution
The paragraph explains that to initiate the reaction between dioxygen and other elements, some external heating is required, as the bond dissociation enthalpy of the oxygen-oxygen (O-O) double bond is high (493.4 kJ mol⁻¹). Heating lowers this bond dissociation enthalpy.