when acidified hydrogen peroxide is mixed with potassium iodide, which gas is produced?

Answer 1

Lancenigo di Villorba (TV), Italy

I AGREE NOT WITH PREVIOUS ANSWER.
When I put some potassium iodide in an aqueous solution of an acid and hydrogen peroxide, I see a fast darkening of the medium.
This process is driven by some electrochemical half-reactions, as follows :

-) 2 KI(aq) ---> 2 K+(aq) + I2(aq) + 2e (+0.55 V)
-) H2O2(aq) + 2 H+(aq) + 2e ---> 2 H2O(aq) (+1.77 V)
-) H2O2(aq) ---> O2(g) + 2 H+(aq) + 2e (+0.68 V)

Since the electrochemical potential overwritten you stated you obtain IODINE's vapours instead OXYGEN's bubbles, as follows :

2 KI(aq) + H2O2(aq) + 2 H+(aq)--->
---> 2 K+(aq) + I2(aq) + 2H2O(aq)

Iodine leaves its vapours, it is true!
In effects, you can put a small paper-piece wetted by an aqueous STARCH's solution. Iodine's vapours will overcome onto the paper colouring itself in blackish hue. You confirmed iodine's volatility.

I hope this helps you.

Answer 2

Acidified Hydrogen Peroxide

Answer 3

Iodide ion is a reducing agent only, forcing the hydrogen peroxide to be an oxidising agent. Under aqueous conditions, iodine vapour cannot possibly be produced, but brown iodine solution instead.

H2O2 + 2H+ + 2e- ----> 2H2O
2I- ----> I2 + 2e-

If a gas is produced, it can only be by the separate catalytic decomposition of hydrogen perioxide:

2H2O2 ----> 2H2O + O2.

Answer 4

Hydrogen peroxide is strong oxidising agent.Its liberated
the nascent oxygen.react with potassium iodide,Iodine
gas will come.

Answer 5

Oxygen