Question

Which colour is shown by the permanganate ion?

Answer 1

Hint: Permanganate induces grafting reactions between the natural fibers and therefore the polymer matrix. Permanganate like permanganate of potash ($KMnO_4$) roughens the natural fibre surface and produces mechanical interlocks with the matrix almost like alkali treatment. Hence, the interfacial bonding between permanganate treated natural fibre and matrix is improved.

Complete answer:
Potassium permanganate is an oxidising agent with disinfectant, deodorising and astringent properties. Its formula is $KMnO_4$. $KMnO_4$ features a deep purple colour. The metal ions in $KMnO_4$ contain d electrons and, therefore, charge transfer occurs from $O^–$ to $Mn^+$. The color of $KMnO_4$ is thanks to charge transfer transitions by absorption of light .
• Potassium permanganate is employed extensively within the water treatment industry.
• A major application of $KMnO_4$ is as a reagent for the synthesis of organic compounds.
• Potassium permanganate is one among the principal chemicals utilized in the film and tv industries.
Actually, the Permanganate ion shows a purple colour.
Natural fibers and their composites
In Tribology of natural fibre Polymer Composites, 2008
 Permanganate treatment
Permanganate induced grafting reactions between the natural fibers and therefore the polymer matrix. Permanganate like permanganate of potash ($KMnO_4$) roughens the natural fibre surface and produces mechanical interlocks with the matrix almost like alkali treatment. Hence, the interfacial bonding between permanganate treated natural fibre and matrix is improved.
Permanganate may be a compound that contains the permanganate group $MnO^{−4}$. Permanganate treatment results in the formation of cellulose radicals through $MnO^{−3} $ ion formation. Then, highly reactive $Mn^{+3}$ ions are liable for initiating graft copolymerization.

Note:
Potassium permanganate ($KMnO_4$) is colored because it absorbs light within the visible range of the spectrum.This charge transfer takes place when a photon of sunshine is absorbed, which results in the purple color of the compound.