For which of the following the $E^{\ominus}\left(M^{3+} / M^{2+}\right)$ is negative?

If $E_{\mathrm{Fe}^{2+} / \mathrm{Fe}}^{\circ}=-0.441 \mathrm{~V}$ and $E_{\mathrm{Fe}^{3+} / \mathrm{Fe}^{2+}}^{\circ}=0.771 \mathrm{~V}$, the standard emf of the cell reaction $\mathrm{Fe}(s)+2 \mathrm{Fe}^{3+}(a q) \longrightarrow 3 \mathrm{Fe}^{2+}(a q)$ is

The specific conductance of 0.05 M NaOH solution is $0.0115 \mathrm{~S} \mathrm{~cm}^{-1}$ What is its molar conductance ( $\wedge_{\mathrm{m}}$ ) in $\mathrm{Scm}^2 \mathrm{~mol}^{-1}$ ?

What is $E_{\text {cell }}$ (in V) of the following cell at $298 \mathrm{~K} ?$

$$ \begin{aligned} & \left(E_{\mathrm{Zn}^{2+} / \mathrm{Zn}}^{\ominus}=-0.76 \mathrm{~V} ; E_{\mathrm{Ni}^{2+} / \mathrm{Ni}}^{\ominus}=-0.25 \mathrm{~V} ; \frac{2.303 R T}{F}=0.06 \mathrm{~V}\right) \\ & 1(s) \mathrm{Zn}^{2+}(0.01 \mathrm{M}) \mathrm{Ni}^{2+}(0.1 \mathrm{M}) \mathrm{Ni}(s \end{aligned} $$