Import Question JSON

$\text{Hint: Endothermic reaction, } \Delta\text{H} = + \text{Ve}$ $\text{In an endothermic reaction, energy is absorbed from the surroundings, resulting in a positive enthalpy change (}\Delta\text{H} = + \text{Ve}).$ $\text{Let's analyze each option:}$ $\text{1. Combustion of methane (CH}_4 + \text{2O}_2 \rightarrow \text{CO}_2 + \text{2H}_2\text{O}): \text{This is an exothermic reaction where energy is released to the surroundings as heat. For combustion reactions, }\Delta\text{H is negative (}\Delta\text{H} = - \text{Ve}).$ $\text{2. Decomposition of water (H}_2\text{O} \rightarrow \text{H}_2 + \frac{1}{2}\text{O}_2\text{): This requires energy input to break the bonds in water molecules, making it an endothermic process with a positive enthalpy change.}$ $\text{3. Dehydrogenation of ethane or ethylene: These reactions involve removing hydrogen atoms from the hydrocarbon molecules, which requires energy input, making them endothermic reactions.}$ $\text{4. Conversion of graphite to diamond: This transformation requires energy to rearrange the carbon atoms from a planar structure (graphite) to a tetrahedral structure (diamond), making it an endothermic process.}$ $\text{Decomposition of water, dehydrogenation of ethane or ethylene, and conversion of graphite to diamond are all examples of endothermic reactions, but combustion of methane is an example of an exothermic reaction.}$ $\text{Therefore, the answer is Option 1: Combustion of methane.}$