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Properties of Potassium permanganate (KMnO 4 ) 1. Potassium permanganate (KMnO 4 ): Action of Heat Potassium permangante on strong heating gives potassium manganate, manganese dioxide and oxygen. 2 KMnO 4 ----------> K 2 MnO 4 + MnO 2 + O 2 2. Oxidising properties of Potassium permanganate (KMnO 4 ) Potassium permanganate is a powerful oxidizing agent in alkaline or acidic solution. The relevant half reactions are: 1. Alkaline medium (pH > 7) MnO 4 - + 2H 2 O + 3 e - ----------> MnO 2 + 4OH - 2. Acidic medium (pH <7) MnO 4 - + 8H + + 5e - ----------> Mn 2+ + 4H 2 O A few important oxidizing reactions of Potassium permanganate ( KMnO 4 ) 1. In acidic medium potassium permanganate oxidizes green ferrous salts to yellow ferric salts MnO 4 - + 8H + + 5Fe 2+ ----------> 5Fe 3+ + Mn 2+ + 4H 2 O 2. in acidic medium potassium permanganate oxidizes oxalic acid or oxalate salts to CO 2 and water 2 MnO 4 - + 16H + + 5 C 2 O ...

Pottassium Permanganate ( KMnO 4 ) is prepared from Pyrolusite ore ( MnO 2 ). The finely powdered Pyrolusite ore ( MnO 2 ) is fused with an alkali metal hydroxide like KOH in the presence of air or an oxidizing agent like KNO 3 to give the dark green potassium Manganate ( K 2 MnO 4 ). Potassium manganate disproportionate in a neutral or acidic solution to give potassium permanganate . 2 MnO 2 + 4 KOH + O 2 ----------> 2K 2 MnO 4 + 2H 2 O 3 MnO 4 2- + 4H + ------------> 2MnO 4 - + MnO 2 + 2H 2 O Commercially potassium permanganate is prepared by the alkaline oxidative fusion of Pyrolusite ore ( MnO 2 ) followed by the electrolytic oxidation of manganate (4) ion . 2 MnO 2 + 4KOH + O 2 -----------> 2 K 2 MnO 4 + 2H 2 O MnO 4 2- ------( electrolytic oxidation )----> MnO 4 - + e - Properties Potassium permanganate forms dark purple (almost black) crystals , which are iso structural with those of KCLO 4 . It has weak temperature dependent...

Preparation of Potassium dichromate ( K 2 Cr 2 O 7 ) Potassium dichromate (K 2 Cr 2 O 7 ) is prepared from chromite ore FeCr 2 O 4 . The chromite ore is fused with sodium or potassium carbonate in free access of air. 4FeCr 2 O 4 + 8Na 2 CO 3 + 7O 2 -------> 8Na 2 CrO 4 + 2FeO 3 + 8CO 2 The yellow solution of sodium chromate is filtered and acidified with sulfuric acid to give a solution from which orange sodium dichromate , Na2Cr2O7 2H2O can be crystallized. 2Na 2 CrO 4 + 2H + ---------> Na 2 Cr 2 O 7 + 2Na + + H 2 O Sodium dichromate is more soluble than potassium dichromate. Hence sodium dichromate when fused with KCl forms orange crystals of potassium dichromate. Na 2 Cr 2 O 7 + 2KCl --------> K 2 Cr 2 O 7 + 2NaCl The chromates and dichromates can be inter convertible. 2CrO 4 2- + 2H 2+ ---------> Cr 2 O 7 2- + H 2 O Cr 2 O 7 2- + 2OH- ---------> 2CrO 4 2- + H 2 O The dichromate ion and chromate ion exist in equilibrium with each other at a pH of ...

Copper sulphate penta hydrate is known as blue vitirol and is the most common oxosalt of copper(2) Preparation Copper sulphate is prepared industrially by blowing a current of air through copper scrap and dilute sulphuric acid. 2Cu + 2H2O + O2 --------> 2CuSO4 + 2H2O The crude copper(2) sulphate solution obtained contain iron(2) sulphates as impurity Dilute nitric acid is added to oxidize iron(2) to iron(3) sulphate which remains in solution after crystallization and CuSO4 5H2O crystallizes out. The crystalline copper(2) sulphate, CuSO4 5H2O has the structure in which four water molecules are coordinated to the central copper cation in square planar structure. The fifth water molecule is held by hydrogen bonds between a sulphate anion and a coordinated water molecule. The fifth hydrogen bonded water molecule is deeply embedded in the crystal lattice and hence not easily removed. Properties 1. Copper sulphate penta hydrate is a blue coloured crystalline solid, soluble in water. 2. Ac...