8.1. Aldehydes and ketones — Chemistry STD 12 Science — Question

$Fe^{3+} + e \to Fe^{2+}\, ;\, E^o = 0.771\,volt$

$I_2 + 2e \to 2I^-\, ;\, E^o = 0.536\,volt$

$E^o$ cell for the cell reaction

$2Fe^{3+} + 2I^-\to 2Fe^{2+}+ I_2$ is 

$[ R =$ gas constant, $F =$ Faraday constant, $T =$ Temperature $]$

$(A)$ For the reaction, $M (s)+2 H ^{+}(a q) \rightarrow H _2(g)+ M ^{2+}(a q)$, if $\frac{ dE _{c o l l}}{ dT }=\frac{ R }{ F }$, then the entropy change of the reaction is $R$ (assume that entropy and internal energy changes are temperature independent).

$(B)$ The cell reaction, $Pt (s) \mid H _2(g, 1$ bar $)\left| H ^{+}(a q, 0.01 M ) \| H ^{+}(a q, 0.1 M )\right| H _2(g, 1 bar ) \mid Pt (s)$, is an entropy driven process.

$(C)$ For racemization of an optically active compound, $\Delta S >0$.

$(D)$ $\Delta S >0$, for $\left[ Ni \left( H _2 O \right)_6\right]^{2+}+3$ en $\rightarrow\left[ Ni ( en )_3\right]^{2+}+6 H _2 O$ (where en $=$ ethylenediamine).