Q$1$: a$)$ Define passivity.

b$)$ A copper sheet of dimensions $9cm4cm1cm,$ is exposed to an acid solution, after $24$ hours, the loss of copper due to corrosion is $15{10}^{-3}$ grams. Calculate:

the current density $($i$)$ in $\frac{A}{c}{m}^2,$

the corrosion rate $CR$ in $m\frac{m}{y}.$

$=\frac{a*}{nF}+i$

$CR=$

knowing that atomic weight $=63\mathrm{.}54\frac{g}{m}ol,=8\mathrm{.}96\frac{g}{c}{m}^3.$

Q$2$: For the corrosion cell: $Fe|F{e}^{+2}({10}^{-3})||C{u}^{+2}({10}^{-4})|Cu$

Draw the cell and write equations to describe the reactions which occur at each electrode?

Calculate the maximum possible potential of the resulting corrosion cell? Eell $=?$

Which electrode is the anode in this corrosion cell & why?

Draw the polarization diagram of this cell and label on it all the important information. Consider the $i_{o,H2}={10}^{-8}$ for copper & $i_{o,H2}={10}^{-6}$ for iron.

i$.$ Draw the diagram indicating all the important points on it$?$

ii$.$ What applied current is necessary to cause passivation?

iii. What applied current is necessary to maintain passivity?

Epp of $0\mathrm{.}1V($SCE$),$ and a critical anodic current density icrit. of $1m\frac{A}{c}{m}^2,$ passive current of $1\frac{A}{c}{m}^2$ and the breakdown potential $0\mathrm{.}5V$ :

Q$3$:

a$)$ An active $-$ passive metal in particular corrosion media has a primary passive potential Epp of $0\mathrm{.}1V(SCE),$ and a critical anodic current density icrit. of $1m\frac{A}{c}{m}^2,$ pass current of $1\frac{A}{c}{m}^2$ and the breakdown potential $0\mathrm{.}5V$ : i$.$ Draw the diagram indicating all the important points on it$?$