For advertisement, the coloured discharged tubes contain :

• He

• Ne

• Ar

• Kr

492.

Which one of the following compounds, is not a protonic acid ?

• SO(OH)₂

• SO₂(OH)₂

• B(OH)₃

• PO(OH)₃

Which of the following is anhydride of perchloric acid ?

• Cl₂O₇

• Cl₂O₅

• Cl₂O₃

• HClO

The oxidation states of iodine in HIO₄ H₃IO₅ and H₅IO₆, are respectively :

• + 1, + 3, + 7

• + 7, + 7, + 3

• + 7, + 7, + 7

• 7, + 5, + 3

Amphoteric-oxide combinations are in:

• ZnO, K₂O, SO₃

• ZnO, P₂O₅, Cl₂O₇

• SnO₂, Al₂O₃, ZnO

• PbO₂, SnO₂, SO₃

The element having highest electron affinity is :

• bromine

• iodine

• fluorine

• chlorine

The correct order according to size is :

• O > O^- > O^2-

• O^- > O^2- >O

• O^2- >O^- > O

• O > O^2- >O^-

pH of a 0.0001M HCl solution is

• 4.0

• 2.0

• 6.0

• 7.0

Pb reacts with dilute HNO₃ produces:

• NO

• NH₄NO₃

• N₂O₅

• NO₂

End-product of the hydrolysis of XeF₆ is:

• XeF₄O

• XeF₂O₂

• XeO₃

• XeO${}_3^{-}$