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Standard XII

Chemistry

Oxides and Oxoanions

A black, wate...

Question

A black, water insoluble powder (A) liberates yellowish green gas (B) on treatment with conc. HCl and (A) dissolves to give a clear solution. Solid (A) when heated with $P b O_{2}$ and $H N O_{3}$ (or) sodium bismuthate & $H_{2} S O_{4}$ gives a purple solution (C). The purple solution is due to the formation of

M n O_{4}^{-}

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M n O_{4}^{2 -}

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M n^{+ 4}

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M n_{2} O_{3}

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Solution

The correct option is A $M n O_{4}^{-}$
$M n O_{2} + 4 H C l \to M n C l_{2} + 2 H_{2} O + C l_{2}$
(A) (B)
$3 M n O_{2} + 3 P b O_{2} + 6 H N O_{3} \to 2 H M n O_{4} + 3 P B (N O_{3})_{2} + 2 H_{2} O (P u r p l e) 4 M n O_{2} + 6 N a B i O_{3} + 10 H_{2} S O_{4} \to 4 N a M n O_{4} + 3 B i_{2} (S O_{2})_{3} N a_{2} S O_{4} + 10 H_{2} O$

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A black, water insoluble powder (A) liberates yellowish green gas (B) on treatment with conc. HCl and (A) dissolves to give a clear solution. Solid (A) when heated with PbO2 and HNO3 (or) sodium bismuthate & H2SO4 gives a purple solution (C). The purple solution is due to the formation of

The correct option is A MnO−4 MnO2+4HCl→MnCl2+2H2O+Cl2 (A) (B) 3MnO2+3PbO2+6HNO3→2HMnO4+3PB(NO3)2+2H2O(Purple)4MnO2+6NaBiO3+10H2SO4→4NaMnO4+3Bi2(SO2)3Na2SO4+10H2O