31.

Many compounds are formed by carbon atom because of its :

• more reactivity

• covalent and ionic nature

• variable valency

• catenation nature

When magnesium is heated , the another compound formed with MgO is :

• Mg₃N₂

• Mg(NO₃)₂

• MgCO₃

• Mg(NO₃)₃

The C-H bond energy in ethane , ethene and ethyne :

• more in ethene

• more in ethane

• more in ethyne

• same in all these

Which of the following is not a redox reaction ?

• KCN + Fe(CN)₂ $\to$K₄[Fe(CN)₆]

• Rb + H₂O $\to$ RbOH + H₂

• H₂O₂ $\to$ H₂O + O

• CuI₂ $\to$ CuI + I₂

The prefix word 'alkali' for alkaline metals shows :

• lustre of silver

• ashes of plant

• metallic nature

• active metal

Potassium nitrate is called :

• Mohr's salt

• Chile salt petre

• Indian salt petre

• Gypsum

Which salt is insoluble in water ?

• NH₄Cl

• KCl

• Na₂SO₄

• NaCl

Which one is colourless ?

• Co²⁺

• Ni²⁺

• Fe³⁺

• Cu⁺

In first transition series, which element show maximum oxidation states :

• Co

• Mn

• Cr

• Fe

The most paramagenetic is :

• Cr³⁺

• Co²⁺

• Mn²⁺

• Fe²⁺