The incorrect statement(s) among (a) - (c) is (are) : (a) W ( VI ) is more stable than Cr ( VI ) . (b) in the presence of HCl , permanganate titrations provide satisfactory results. (c) some lanthanoid oxides can be used as phosphors

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(a) In transition metals on moving down the group higher oxidation states are more stable due to smaller size of atoms, due to lanthanide and actinide contractions. (b) KMnO 4 can oxidise chloride into chlorine, so it will give incorrect results (c) its a fact