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

The compound with maximum covalent character is :

• AlCl₃

• AlI₃

• AgI₂

• NaI

774.

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

Which is correct regarding size of atom?

• N < O

• B < Ne

• V > Ti

• Na > K

Which of the following is not sp² hybridised?

• Graphite

• Graphene

• Fullerene

• Dry ice

Choose the correctly paired gaseous cation and its magnetic (spin only) moment (in B.M.)

• Ti²⁺,3.87 B.M.

• Cr²⁺, 4.90 B.M.

• Co³⁺,3.87 B.M.

• Mn²⁺,4.90 B.M.

In O₃ molecule, the formal charge on the central O-atom is

• 0

• -1

• -2

• +1