Potassium iodide, KI, is used as a reagent in both inorganic and organic chemistry. KI slowly oxidises in air, forming $$\(\mathrm{I}_{2}\)$$. $$\[ \text { reaction } 1 \quad 4 \mathrm{KI}(\mathrm{s})+2 \mathrm{CO}_{2}(\mathrm{~g})+\mathrm{O}_{2}(\mathrm{~g}) \rightarrow 2 \mathrm{~K}_{2} \mathrm{CO}_{3}(\mathrm{~s})+2 \mathrm{I}_{2}(\mathrm{~s}) \quad \Delta H^{\ominus}=-203.4 \mathrm{~kJ} \mathrm{~mol}^{-1} \]$$ Table 1.2 shows some data relevant to this question. (i) Calculate the standard entropy change, $$\(\Delta S^{\ominus}\)$$, of reaction 1 . $$\[ \Delta S^{\ominus}=\ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \ldots \mathrm{JK}^{-1} \mathrm{~mol}^{-1} \]$$ (ii) Use your answer to (c)(i) to show that reaction 1 is spontaneous at 298 K . (iii) The Group 1 carbonates are much more thermally stable than the Group 2 carbonates. State and explain the trend in the thermal stability of the Group 2 carbonates. ....................................................................................................................................... . ....................................................................................................................................... . ....................................................................................................................................... . .................................................................................................................................

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