Given the following entropy values ( in `JK^(-1) "mol"^(-1)`) at 298 K and 1 atm: `H_(2)(g):130.6, Cl_(2)(g):223.0, HCl(g): 186.7`. The entropy change

Monjur Alahi

Given the following entropy values ( in `JK^(-1) "mol"^(-1)`) at 298 K and 1 atm: `H_(2)(g):130.6, Cl_(2)(g):223.0, HCl(g): 186.7`. The entropy change (in `JK^(-1) "mol"^(-1)`) for the reaction
`H_(2)(g) + Cl_(2)(g) to 2HCl(g)` , is
A. `+540.3`
B. `+727.0`
C. `-166.9`
D. `+19.8`


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Salim Ahmed Kawsar

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Correct Answer - D
`H_(2)(g) + Cl_(2)(g) to 2HCl(g) `
`Delta_(I)S=sumS_(m)""^(@)(P) -sumS_(m)""^(@)(R)`
`Delta_(I)S^(@)=2xxS_(m)^(@)(HCl) - [S_(m)^(@)(Cl_(2)) + S_(m)^(@) (H_(2))]`
`=(2xx186.7)-(223+ 130.6)`
`=373.4-353.6`
`=+19.8 JK^(-) "mol"^(-)`

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