An element belongs to group 15 and third period of the Periodic Table. Its electronic configuration will be:

• 1s²2s²2p³

• 1s²2s²2p⁴

• 1s²2s²2p⁶3s²3p³

• 1s²2s²2p⁶3s²3p²

Which one of the following is paramagnetic?

• N₂

• NO

• CO

• O₃

Which of the following is used to prepare Cl₂ gas at room temperature from concentrated HCl?

• MnO₂

• H₂S

• KMnO₄

• Cr₂O₃

NO₂ is not obtained on heating:

• AgNO₃

• KNO₃

• Cu(NO₃)₂

• Pb(NO₃)₂

Which of the following is a polar molecule?

• BF₃

• SF₄

• SiF₄

• XeF₄

P₄O₁₀ is the anhydride of

• H₃PO₂

• H₃PO₃

• H₃PO₄

• H₄P₂O₇

Of the following acids the one which has the capability to form complex compound and also possesses oxidising and reducing properties is

• HNO₃

• HNO₂

• HCOOH

• HCN

Atoms in a P₄ molecule of white phosphorus are arranged regularly in the following way

• at the corners of a cube

• at the corners of an octahedron

• at the corners of a tetrahedron

• at the centre and corners of a tetrahedron

179.

Which one of the following pairs is obtained on heating ammonium dichromate?

• N₂ and H₂O

• N₂O and H₂O

• NO₂ and H₂O

• NO and NO₂

When KI is added to acidified solution of sodium nitrite, then

• NO gas is liberated and I₂ is set free

• N₂ gas is liberated and HI is produced

• N₂O gas is liberated and I₂ is set free

• N₂ gas is liberated and HOI is produced