In a sealed flask, colourless NOBr partially decomposes into colourless NO and reddish-brown Br 2 vapour: 2NOBr(g) ⇌ 2NO(g) + Br 2 (g). When the flask is warmed, the reddish-brown colour deepens, and

Question

In a sealed flask, colourless NOBr partially decomposes into colourless NO and reddish-brown Br 2 vapour: 2NOBr(g) ⇌ 2NO(g) + Br 2 (g). When the flask is warmed, the reddish-brown colour deepens, and on cooling it fades. The enthalpy change for the forward reaction is

TestHub · Accepted Answer

Warming deepens the brown color, indicating that heating shifts the equilibrium towards Br₂. This means the reaction proceeds in the forward direction. According to Le Chatelier's principle, a reaction that shifts forward upon heating is endothermic, implying that ΔH is positive. Therefore, option (b) is correct.

Chemistry - Thermochemistry Question with Solution | TestHub

Options:

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