When MnO₂ is heated with PbO₂ and conc. HNO₃ pink colour is obtained due to formation of

• KMnO₄

• HMnO₄

• Pb(MnO₄)₂

• PbMnO₂

142.

Which of the following ions has the highest magnetic moment ?

• Zn²⁺

• Ti³⁺

• Sc³⁺

• Mn²⁺

In nitroprusside ion, the iron and NO as Fe²⁺ and NO⁺ rather than Fe³⁺ and NO. These forms can be differentiated by

• estimating the concentration of iron

• measuring the concentration of CN^-

• measuring the solid state magnetic moment

• thermally decomposing the compound

Which of the following compounds gives PELIGOT's salt with chromyl chloride?

• Borax

• Oxone

• Sylvine

• Trona

In the following, the element withthe highest electropositivity is

• copper

• silver

• gold

• caesium

Mark the wrong statement. When Na₂S is added to sodium nitroprusside solution,

• beautiful violet colour is produced

• a complex [Fe(CN)₅NOS]^4- is formed

• a complex [Fe(CN)₅NOS]^2- is formed

• a complex [Fe(CN)₅NOS] is formed

Iron loses magnetic property at

• melting point

• 1000 K

• Curie point

• boiling point

Stainless steel does not rust because

• chromium and nickel combine with iron

• chromium forms an oxide layer and protects iron from rusting

• nickel present in it, does not rust

• iron forms a hard chemical compound with chromium present in it

The atomic number of Ni and Cu are 28 and 29 respectively. The electronic configuration. 1s²2s²2p⁶3s²3p⁶3d¹⁰ represents.

• Cu⁺

• Cu²⁺

• Ni²⁺

• Ni

Which of the following types of metals form the most efficient catalysts ?

• Alkali metals

• Alkaline earth metals

• Transition metals

• All of the above