Lawrie Ryan and Roger Norris Solutions for Chapter: Electrochemistry, Exercise 9: Questions

Suggest why aqueous silver nitrate is not used in a salt bridge when connecting a half-cell containing $\mathrm{Zn}$ and $1.00 \mathrm{mol} {\mathrm{dm}}^{-3} {\mathrm{ZnCl}}_2\left(\mathrm{aq}\right)$ to another half-cell.

Write half-equation for the reaction taking place in the half-cell below. Write the equation as a reduction (electrons on the left-hand side of the equation). 
${\mathrm{Cr}}^{2+} / {\mathrm{Cr}}^{3+}$

Write half-equation for the reaction taking place in the half-cell below. Write the equation as a reduction (electrons on the left hand side of the equation).
${\mathrm{Br}}_2 /2{\mathrm{Br}}^{-}$

Write half-equation for the reaction taking place in the half-cell below. Write the equation as a reduction (electrons on the left hand side of the equation).
${\mathrm{O}}_2 + {\mathrm{H}}_2\mathrm{O}/{\mathrm{OH}}^{-}$ (make sure that you balance the equation)

Write half-equation for the reaction taking place in the half-cell below. Write the equation as a reduction (electrons on the left hand side of the equation).
${\mathrm{VO}}^{2+} + {\mathrm{H}}_2\mathrm{O}/{\mathrm{VO}}_2^{+} + {\mathrm{H}}^{+}$ (make sure that you balance the equation)