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Question
Answer the following:
Predict whether the following reaction would occur spontaneously under standard state condition.
`2"Br"_(("aq"))^(-) + "Sn"_(("aq"))^(2+) -> "Br"_(2("l")) + "Sn"_(("s"))`
Solution
`2"Br"_(("aq"))^(-) + "Sn"_(("aq"))^(2+) -> "Br"_(2("l")) + "Sn"_(("s"))`
At anode: `2"Br"_(("aq"))^(-) -> "Br"_(2("l")) + 2"e"^(-)`
At cathode: `"Sn"_(("aq"))^(2+) + 2"e"^(-) -> "Sn"_(("s"))`
From the electrochemical series we have,
`"E"_("Br"_2)^circ` = 1.080 V and `"E"_"Sn"^circ` = - 0.136 V
For cell having `"Br"_(2("l"))` as anode and Sn as cathode.
`"E"_"cell"^circ = "E"_"Sn"^circ - "E"_("Br"_2)^circ`
= - 0.136 V - 1.080 V
`"E"_"cell"^circ` = - 1.216 V
Emf of cell being negative, the given cell reaction is nonspontaneous.
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