Question

1. You put 1 mL of CH4 into a test tube with 1 mL of KI (aq). Then you add a small amount of a metal salt, MNO, (aq), and shake the mixture. (a) If the M reacts with, and oxidizes the 1'. what colour would the CH 4 be? Explain and give any relevant reactions. (1 mark) does not react with the l'? Explain. (b) What colour would the C6H 4 be if the M (1 mark) 2. Consider Pb2+ + 2e 7 Pb Using any Data Sheet, find a metal M M2+ + 2e 7 M such that the lead half-cell is the anode, the M half-cell is the cathode and the overall is Ecell positive. Write the overall reaction and give the value of Ecell. (1 mark) 3. The measured potential of the following cell was 0.1776 volts. Pb/Pb2+ (?M )||Pb2+ (1.0M)|Pb Calculate the electrode potential of the unknown half-cell (anode). (0.5 mark)

Answer 1

The solutions to problems 1,2 and 3 are provided in the images attached. Don't forget to give a thumbs up to the solution!!
- At Anode Pb 2+2e (8M) Pb 20 (1M) are Pb Al Cathode -3. (Reactant] 5 Pb + Pb2+ Pb2+ + Pb Querall Reactions S CIM) M (RM) Uring Neonist reaction - hotels and Free - Ecele - 0.0591 log [product] E cell = tired" - E oxid" = OU Sunce, both half-cells correspond to the same element (lead w e E cell = 0 - 0.059 lof [P627 0.1776 = -0.059 1 log [Pb 27 Elbeton concentration 9. 76 810M As IM

become b- do Pb2+ + 2i = Pb Inquestion, dead is the anode, the sxn will At anode Pbo ~ Pb 2 a 20 E = 6.130 At cathode M e Le ? M E = ? The electrode polential is given by an Ecelu = Ereduction - E oxidation Creduction - 0.13) v treduction should be > 0.13V for focitie trece - Preduction values for Cu 2 u and Inte/sn20 puis is 0.340 and 0.150 respectively. uch 0./3V. - Thus, M2/M pair would be cu 2 / Ce Ecole - (0.34 - 0.13) V =)[0.216] -Eicle reaction = Pb & Cu 2 P621 + Cu

IJ M + the reaction Ot (a) CH4 is colourless liquid. reacts with KI and ouudises it, will be of M + +21 - Ig & M Onidation Reduction 5. KI onidises lo Is which is violet in colour in solution. Thus, when CH4 is reacted with KI and a Amall amount of metal salt MNO₂ the colour of the solution will become violet. (6) gf me does not react /onidise I, then no I formation occurs and the solution remains colourless.