Question

Q4: The following is the reaction when iron corrodes in an acid: Fe+2HCl(aq)+{ 0, -> FeCl,(aq) + 4,0 a) In what direction shall the reaction proceed if the activity of Fe2+ is 1, and a(H) = 1? Feat would be b) If the temperature is maintained at 25°C, what activity of iron required to stop the corrosion in acid?

Answer 1

Sell Given Iron corrodes in an Fe + 2HCl can +10 and feel, can) + H2O Now, E' =1:68V * At anode, the reaction takes place I - referat ze & -0.45 At cathode, the reaction takes place I 10x + 2 H 4144) +24 H201 = 9.23 V Thus, onuall reaction is z. fe cs +40(g) + 2 Home -> Fetus + My Oly & overall cell potential in Centrode Eanode = 1:23-(-0:48) Now, By using Nernst equation I . Ez € - So RT lay ve Frame where E = Electrochemical potential t° - Electrochemical potential at standard conditions R= Universal gas constant T= Temperature f = Farday's constant. n = No. of elections. ased & don = Activity of seduced & onidized 1. species Now, butting the values of R, T&F unde standard 0.0591 ha [aged] Ez € - 0.00u lej w samh

as Ciren, Activity of & re , a rect=1 aut at de total 2 electrons, Hence, = f-0.012! blog. 51.6870 1168 Since hence LE=168 the elbochemical potential rakce is positive the reaction will proceed in forward direction. - 61 Ciren, "Temperature, is 25°C. Since the corrosion has stopped de t means forward & backward reaction is equal o . It. Hence, [feet € = -0.0531 Lagi Trener Es grotel Leyne le Assume the activity of 4t is t, thes, 4-0012 by him her 936=16] login [ en - List ml 0019 1 2 - Et = 1856.053 [feet a 1.403 X 1057/ Activity of esc ison
Here, we can notice that value of activity of iron is very small i.e. almost zero which is impossible to reach this value of activity. Hence, stopping of corrosion in iron is very difficult.

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