For the fuel cell reaction:
$2H_{2(g)} + O_{2(g)} \to 2H_2O_{(l)}$; $\Delta_fH^o_{298}(H_2O_{(l)}) = -285.5 \ kJ/mol$
What is $\Delta S^o_{298}$ for the given fuel cell reaction?
Given: $O_{2(g)} + 4H^+_{(aq)} + 4e^- \to 2H_2O_{(l)}$; $E^o = 1.23 \ V$

$A$ battery is made from $Cr$ and $Na_2Cr_2O_7$. When this battery discharges according to the reaction $Na_2Cr_2O_7 + Cr + H^{+} \rightarrow Cr^{3+} + H_2O + Na^{+}$,the chemical equation is unbalanced. If $1 \ F$ (Faraday) of electricity is passed during the charging of the battery,what is the number of moles of $Cr^{3+}$ removed from the solution (in $/3$)?

At $298 \ K$,the equilibrium constant is $2 \times 10^{15}$ for the reaction:
$Cu_{(s)} + 2 Ag^{+}_{(aq)} \rightleftharpoons Cu^{2+}_{(aq)} + 2 Ag_{(s)}$
The equilibrium constant for the reaction $\frac{1}{2} Cu^{2+}_{(aq)} + Ag_{(s)} \rightleftharpoons \frac{1}{2} Cu_{(s)} + Ag^{+}_{(aq)}$ is $x \times 10^{-8}$. The value of $x$ is (Nearest Integer).

Tollen's reagent is used for the detection of aldehyde. When a solution of $AgNO_3$ is added to glucose with $NH_4OH$,gluconic acid is formed.
$Ag^{+} + e^{-} \rightarrow Ag ; E^{\circ}_{red} = 0.8 \ V$
$C_6H_{12}O_6 + H_2O \rightarrow C_6H_{12}O_7 + 2H^{+} + 2e^{-} ; E^{\circ}_{oxd} = -0.05 \ V$
$Ag(NH_3)_2^{+} + e^{-} \rightarrow Ag_{(s)} + 2NH_3 ; E^{\circ}_{red} = 0.337 \ V$
[Use $2.303 \times \frac{RT}{F} = 0.0592$ and $\frac{F}{RT} = 38.92$ at $298 \ K$]
$1.$ $2Ag^{+} + C_6H_{12}O_6 + H_2O \rightarrow 2Ag_{(s)} + C_6H_{12}O_7 + 2H^{+}$. Find $\ln K$ of this reaction.
$(A) \ 66.13 \quad (B) \ 58.38 \quad (C) \ 28.30 \quad (D) \ 46.29$
$2.$ When ammonia is added to the solution,$pH$ is raised to $11$. Which half-cell reaction is affected by $pH$ and by how much?
$(A) E_{oxd}$ will increase by a factor of $0.65 \ V$ from $E^{\circ}_{oxd}$
$(B) E_{oxd}$ will decrease by a factor of $0.65 \ V$ from $E^{\circ}_{oxd}$
$(C) E_{red}$ will increase by a factor of $0.65 \ V$ from $E^{\circ}_{red}$
$(D) E_{red}$ will decrease by a factor of $0.65 \ V$ from $E^{\circ}_{red}$
$3.$ Ammonia is always added in this reaction. Which of the following must be incorrect?
$(A) NH_3$ combines with $Ag^{+}$ to form a complex.
$(B) Ag(NH_3)_2^{+}$ is a stronger oxidising reagent than $Ag^{+}$.
$(C)$ In absence of $NH_3$,silver salt of gluconic acid is formed.
$(D) NH_3$ has affected the standard reduction potential of glucose/gluconic acid electrode.
Give the answer for questions $1, 2$ and $3$.

Which of the following statements is $NOT$ correct?

For a spontaneous reaction,determine the values of $\Delta G^o$,equilibrium constant $K$,and $E^o_{cell}$ respectively.