[bblue]

The standard reduction potential for the half-reaction

Sn4+ + 2e- --> Sn2+
is +0.15 V.
Consider data from the table of standard reduction potentials for common half-reactions, in your text.
For a galvanic cell under standard conditions, which of the following cathodic half reactions would produce, at the anode, a spontaneous oxidation of Sn to Sn2+ but not Sn2+ to Sn4+.

2H+ + 2e- --> H2
Pb2+ + 2e- --> Pb
Cu2+ + e- --> Cu+
Sn4+ + 2e- --> Sn2+
Fe2+ + 2e- --> Fe
Sn2+ + 2e- --> Sn

My ans was:
yes
no
no
yes
no
yes

and i also tried
yes
yes
no
yes
no
yes

both ans were wrong
can someone help me?

[sjb]

I think you also need the Eo for Sn(II)  Sn(IV). Is this in your book anywhere?

[zxt]

Those -0.136v<E<0.154v under standard circumstance. -0.136v is E value of half-reaction Sn²⁺+2e- :rarrow:Sn