MCQ
Benzene is obtained by
- ASubstitution of three acetylene molecules
- BAddition of three ${C_2}{H_2}$ molecules
- ✓Polymerisation of three ${C_2}{H_2}$ molecules
- DCondensation of three ${C_2}{H_2}$ molecules
$3CH \equiv CH\mathop {\xrightarrow{{{\text{heat}}}}}\limits_{Cu,\,{{500}\,^o}C} $
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Step $I\,\,:$ ${H_2}O(g)\, \to \,H(g)\, + \,OH(g)\,;$ $\Delta H = 498\,kJ\,mol^{-1}$
Step $II\,\,:$ $OH(g)\, \to \,H(g)\, + \,O(g)\,;$ $\Delta H = 428\,kJ\,mol^{-1}$
The bond enthalpy of the $O-H$ bond is....$kJ\,mol^{-1}$