$A$ saturated solution of $KNO_3$ with agar-agar is used to make a 'salt-bridge' because

Consider the figure and answer the questions $(i)$ to $(vi)$ given below.
$(i)$ Redraw the diagram to show the direction of electron flow.
$(ii)$ Is the silver plate the anode or cathode?
$(iii)$ What will happen if the salt bridge is removed?
$(iv)$ When will the cell stop functioning?
$(v)$ How will the concentration of $Zn^{2+}$ ions and $Ag^{+}$ ions be affected when the cell functions?
$(vi)$ How will the concentration of $Zn^{2+}$ ions and $Ag^{+}$ ions be affected after the cell becomes 'dead'?

Upon dipping a copper rod into an aqueous solution of the salt,the solution that turns blue is

For a general redox reaction:
Anode: $Red_1 \to Ox_1^{n_1+} + n_1 e^-$
Cathode: $Ox_2^{n_2+} + n_2 e^- \to Red_2$
Which of the following statements is incorrect?

At $298 \ K$,the standard electrode potentials of $Cu^{2+}/Cu$,$Zn^{2+}/Zn$,$Fe^{2+}/Fe$ and $Ag^{+}/Ag$ are $0.34 \ V$,$-0.76 \ V$,$-0.44 \ V$ and $0.80 \ V$,respectively. On the basis of standard electrode potential,predict which of the following reactions cannot occur?

Write a note on mercury cell $(Zn-Hg)$.