Question

explain whether corrosion will occur in aerated or deaerated H2SO4 acid? justify your answer by using relevant thermodynamic calculation

Answer 1

The corrosion rates of a rotating cylinder in deareated acid solution was reported

It has been shown that the corrosion rate was independent of of rotation rate. This body of results omplies that iron dissolution and hydrogen evolution are not mass transfer controlled under these circumstances. Similar results leading to the same conclusions on the anodic dissolution of nickel in deareated sulfuric acid solution have been obtained.

The dissolution reaction of copper in deareated sulfuric acid can be represented as

This reaction takes place in two steps

where step 1 is in equilibrium condition and step 2 is the rate limiting conditions. This may imply that Step 2 is the slower step in the reaction sequence i.e., the copper dissolution is an activation controlled process.

in oxygen saturated acid solutions, the corrosion rate of iron increases velocity of the solution.These results can be interpreted as indicating metallic corrision under mass transfer control by cathodic reaction i.e the anodic reaction of iron are activation controlled processes.

In aerated acid solutions, the rate determining step during the dissolution of copper is once again, the oxidation of cuprous ion.

This implies that the anodic dissolution of copper in aerated acid solution is an activation controlled processes.