The correct order of the thermal stability of hydrogen halides (H – X) is

• HI > HBr > HCl > HF

• HF > HCl > HBr > HI

• HCl < HF > HBr < HI

• HCl < HF > HBr < HI

Heating an aqueous solution of aluminium chloride to dryness will give

• AlC_l3

• Al₂Cl₆

• Al₂O₃

• Al₂O₃

In silicon dioxide

• Each silicon atom is surrounded by four oxygen atoms and each oxygen atom is bonded to two silicon atoms

• Each silicon atom is surrounded by two oxygen atoms and each oxygen atom is bonded to two silicon atoms

• Silicon atoms is bonded to two oxygen atoms

• Silicon atoms is bonded to two oxygen atoms

804.

Which one the following statement regarding helium is incorrect?

• It is used to fill gas balloons instead of hydrogen because it is lighter and non – inflammable

• It is used in gas – cooled nuclear reactors

• It is used to produce and sustain powerful superconducting reagents

• It is used to produce and sustain powerful superconducting reagents

One mole of magnesium nitride on the reaction with an excess of water gives

• one mole of ammonia

• two moles of nitric acid

• Two mole of ammonia

• Two mole of ammonia

Beryllium and aluminium exhibit many properties which are similar. But the two elements differ in

• exhibiting maximum covalency in compound

• exhibiting amphoteric nature in their oxides

• forming covalent halides

• forming covalent halides

Aluminium chloride exists as a dimer, Al₂Cl₆ in the solid state as well as in solution of non-polar solvents such as benzene. When dissolved in water, it gives

• Al³⁺ + 3Cl^-

• Al₂O₃ + 6HCl

• [Al(OH)₆] ^3-

• [Al(OH)₆] ^3-

Nitrogen dioxide is not produced on heating

• KNO₃

• Pb(NO₃)₂

• Cu(NO₃)₂

• AgNO₃

In the solid state, PCl₅ exists as

• [PCl₄]^- and [PCl₆]⁺ ions

• covalent PCl₅ molecules only

• [PCl₄]⁺ and [PCl₆]^-

• covalent P₂Cl₁₀ molecules only

The acid in which O-O bonding is present is

• H₂S₂O₃

• H₂S₂O₆

• H₂S₂O₈

• H₂S₄O₆