1)in this process: 2S2O3-2(aq)+I2(s)---->S4O6-2(aq)+2I-(aq)

The I is the gain of electrons
But the other material stay with -2 so he loss or gain electron?


2)3V3+(aq)+V(s)----->3V2+

3V3+ gain electron but what happen with V(s) how can I know how is the Oxidation or the Reduction

Thanks.

Reaction 1: How many sulfur ions are in the starting materials and in the products?
Reaction 2: Something is wrong: the vanadium atoms do not add up.

4 sulfur ions are in the starting materials. And 4 in the products

Yes there a mistake in Reaction 2 is need to be like this:2V3+(aq)+V(s)---->3V2+(aq).

Thanks

I would say there are 2 ions on the left and 1 ion on the right, (there are 4 sulfur ATOMS on each side)

Right.

In the first reaction, it is the S that undergoes a redox.

In the first ion, S2O3 2-, the O.N. of S is +2. Can you see how?

In the second ion, S4O6 2-, the O.N. of S is +2.5. Can you see how?

Hi I solved this Question, BUT still really really thank you for trying to help as you do EVERY TIME :)

You're welcome :)