sulfuric acid as an oxidising agent (1 Viewer)

[Nelly_04]

for the dot point which says to perform a first hand investigation to show sulfuric acid as an oxidising agent, how did most people do this experiment? i think we added sulfuric acid to copper and also to zinc, but i can't remember any observations we made. If anyone knows of observations or results for this experiment could they pls help.
Also, are these the correct equations for the reactions:

- 6Cu + 6H2SO4 --> 4CuSO4 + Cu2S + SO2 + 6H2O

-7Zn + 9H2SO4 --> 7ZnSO4 +S + H2S +8H2O

thanks

 

[mervvyn]

i can't remember exactly because i lost the sheet with the experiment, but it was something along the line of filter paper soaked in potassium chromate of some description (yellow) being decolourised by the action of the sulfuric acid to white (actually a v v v pale green but yeah). I can't remember the exact equation, i should probably find it sometime soon. I think the SO2 does the decolourising - think.

 

[Tommy_Lamp]

Place a small piece of magnesium, zinc and iron (e.g. a nail) in separate beakers or test tubes.
Add 3 drops of the sulfuric acid to each metal and observe.
Record all observations in a table.
Write equations to show any reactions observed.

look at the standard potentials table to see what results are observed and what reactions take place.

 

[nesstar]

We did the copper one - hot conc. sulfuric acid oxidises copper to copper ions. I had a different equation to you though:
Cu(s) + 2HSO4-(aq) + 2H+(aq) --> SO2(g) + Cu2+(aq) + SO42-(aq) + 2H2O(l)
or alternatively,
Cu(s) + 2H2SO4(l) --> CuSO4 (aq) + SO2(g) + 2H2O(l)