N₂O is isoelectronic to CO₂ and ${\mathrm{N}}_3^{-}$. Which of the following is the structure of N₂O ?

• 

• N-O-N

• N-N-O

• 

Number of lone pair in XeOF₄ is :

• zero

• one

• two

• three

Assertion : C- $\underset{..}{\overset{..}{O}}$ - H bond angle is less than the normal tetrahedral bond angle.

Reason : Lone pair-lone pair repulsion decreases bond angle.

• If both assertion and reason are true and reason is the correct explanation of assertion

• If both assertion and reason are true but reason is not the correct explanation of assertion

• If assertion is true but reason is false.

• If both assertion and reason are false.

The geometry of ammonia is :

• tetrahedral

• pyramidal

• triangular

• trigonal bipyrarnidal

Assertion : Diamagnetic substances are not attracted by magnetic field.

Reason : Diamagnetic substances have no unpaired electrons.

• If both assertion and reason are true and reason is the correct explanation of assertion.

• If both assertion and reason are true but reason is not the correct explanation of assertion.

• If assertion is true but reason is false.

• If both assertion and reason are false

Which one have the highest melting point ?

• CsCl

• NH₃

• He

• CHCl₃

507.

The compound with maximum covalent character is :

• AlCl₃

• AlI₃

• AgI₂

• NaI

NF₃ and BF₃ both are covalent , but BF₃ is non-polar, while NF₃ is polar because :

• boron is non-metal in free state , while N₂ is gas

• there is no dipole moment in B-F  bond while N-F bond have some dipole moment

• BF₃ is planar while NF, is pyramidal

• boron atom is smaller than nitrogen atom

The number of $\mathrm{\sigma }$ (sigma) and $\mathrm{\pi }$ (pi) bonds in 1-buene-3-yne is :

• 5$\mathrm{\sigma }$ , 5$\mathrm{\pi }$

• 8$\mathrm{\sigma }$ , 6$\mathrm{\pi }$

• 7$\mathrm{\sigma }$ , 3$\mathrm{\pi }$

• 6$\mathrm{\sigma }$ , 4$\mathrm{\pi }$

The geemetry of the compound of sp³d hybridisation is :

• pyramidal

• triangular

• planar

• trigonal bipyramidal