KO₂ exhibits paramagnetic behaviour. This is due to the paramagnetic nature of

• KO^-

• K⁺

• O₂

• O^-₂

462.

Which one of the following ions has same number of unpaired electrons as those present in V⁺ ion?

• Fe³⁺

• Ni²⁺

• Mn²⁺

• Cr³⁺

Which of the following characteristics of the transition metals is associated with their catalytic activity?

• Colour of hydrated ions

• Diamagnetic behaviour

• Paramagnetic behaviour

• Variable oxidation states

What are X and Y in the following reactions?

$$\begin{gathered} {\mathrm{MnO}}_4^{-} + {\mathrm{I}}^{-} \stackrel{{\mathrm{H}}^{+}}{\to } \mathrm{X} \\ {\mathrm{MnO}}_4^{-} + {\mathrm{I}}^{-} \stackrel{{\mathrm{H}}_2\mathrm{O}}{\to } \mathrm{Y} \end{gathered}$$

• ${\mathrm{I}}_2, {\mathrm{IO}}_4^{-}$

• ${\mathrm{I}}_2, {\mathrm{IO}}_3^{-}$

• ${\mathrm{IO}}_3^{-}, {\mathrm{IO}}_3^{-}$

• ${\mathrm{IO}}_3^{-},{\mathrm{I}}_2,$

Which of the following transition metals shows the highest oxidation state?

• Sc

• Ti

• Mn

• Zn

Which of the ions having following electronic structure would have maximum magnetic moment?

• 1s², 2s², 2p⁶,3s²,3p⁶,3d³

• 1s², 2s², 2p⁶,3s²,3p⁶,3d⁵

• 1s², 2s², 2p⁶,3s²,3p⁶,3d⁷

• 1s², 2s², 2p⁶,3s²,3p⁶,3d⁹

Which of the following ions forms most stable complex compound?

• Cu²⁺

• Ni²⁺

• Fe²⁺

• Mn²⁺

Pb²⁺, Cu²⁺, Zn²⁺ and Ni²⁺ ions are present in a given acidic solution. On passing hydrogen sulphide gas through this solution the available precipitate will contain

• PbS and NiS

• PbS and CuS

• CuS and ZnS

• CuS and NiS

To an acid solution of an anion a few drops of KMnO₄ solution are added. Which of the following, if present will not decolourise the KMnO₄ soltuion?

• NO${}_2^{-}$

• S^2-

• Cl^-

• CO${}_3^{2-}$

AgNO₃ gives red colour with

• NaCl

• NaBr

• NaI

• K₂CrO₄