Me! with q1c.
what can decolourise acidified potassium manganate (vii) solution.
iodine, aqueous sodium hydroxide, ethanol, dilute hydrochloric acid, sodium iodide or aqueous potassium iodide?

To decolorize acidified potassium manganate (VII) solution, you should add dilute sulfuric acid. The solution will then become colorless. Since there is no dilute sulfuric acid, I think dilute hydrochloric acid will do since both are strong acids. Make sure potassium manganate (VII) solution is acidified, if it is somehow alkaline, the solution will produce a dark precipitate. 

Answer) by studying proton collisions hope this : )