Chemical of the Day - Potassium Manganate (VII)

Somehow gc likes easy chemicals o.o maybe we start with easy stuff and move to hardcore mugging later. Potassium manganate (VII) or potassium permanganate is interesting in the sense that the manganese is existing as +7 charge in the compound, which is quite rare even among transition metals, since the maximum oxidation number that an element can exhibit is +8 (which is super rare because most elements will not tend to lose all its 8 electrons)
And seeing that the Mn lost so many electrons, it is quite expected that it would want to gain back some electrons when undergoing chemical reactions. Hence KMnO4 is a strong oxidising agent.


Formula: KMnO4


Appearance: Purple-gray crystals. Purple to magenta solution.
Structure: Giant ionic lattice


Solubility: 6.38g / 100 ml (noober than phenol rofl)


Preparation: (you need a pikachu electricity to do this)
First MnO2 is fused with KOH and heated with a source of oxygen, such as KNO3 or KClO3. This gives K2MnO4 as the product. After which electrolytic oxidation in an alkaline medium would produce KMnO4.
2 MnO₂ + 4 KOH + O₂ → 2 K₂MnO₄ + 2 H₂O
2 MnO₄^2– + Cl₂ → 2 MnO₄^– + 2 Cl^–


Uses:
Inorganic: Used as a standard solution for redox titration in quantitative analysis of reducing agent, such as finding out how much or how concentrated a solution of ascorbic acid is. In this case KMnO4 can undergo 2 types of reduction, first in an acidic medium and second in a non-acidic medium.
In acidic medium:
MnO4- + 8H+ + 5e- -> Mn2+ + 4H2O
In non-acidic medium:
MnO4- + 2H2O + 3e- -> MnO2 + 4OH-
Hence in acidic medium the purple colour will fade to very pale pink (almost colourless), while in non-acidic medium the purple colour will turn to a brown precipitate.


Organic: Used as an oxidising agent to oxidise many organic compounds.
Dilute solution of KMnO4 can oxidise alkenes to diols.
Acidic solution of KMnO4 can cleave (切) C=C bond to form either CO2 & H2O, carboxylic acid or ketone.
CH₃(CH₂)₁₇CH=CH₂ + 2 KMnO₄ + 3 H₂SO₄ → CH₃(CH₂)₁₇COOH + CO₂ + 4 H₂O + K₂SO₄ + 2 MnSO₄
It can oxidise aldehyde to carboxylic acid.
5 C₆H₁₃CHO + 2 KMnO₄ + 3 H₂SO₄ → 5 C₆H₁₃COOH + 3 H₂O + K₂SO₄ + 2 MnSO₄
It can even oxidise alkyl groups on a benzene ring. For example it oxidises toluene to benzoic acid.
5 C₆H₅CH₃ + 6 KMnO₄ + 9 H₂SO₄ → 5 C₆H₅COOH + 14 H₂O + 2 K₂SO₄ + 6 MnSO₄

Other stuff:
It can be used as an antiseptic and disinfectant due to its oxidising nature. (Hence you can buy it from Guardian in dilute solutions meant for treating cuts and stuff)
Reaction of solild KMnO4 with pure glycerol or simple alcohols result in violent combustion.
Reaction with conc H2SO4 produces Mn2O7, which (unsurprisingly) explodes due to instability.
Can rapidly stain any organic material, thought it can be cleaned by washing with a reducing agent (such as ascorbic acid)
Used in banana shipments to absorb the ethene produced by ripening bananas to lengthen their ripening time (wow).

Ok now gc can go and do cyclohexane.