The geometry of methane molecule is :

• tetrahedral

• pyramidal

• octahedral

• square planar

Heisenberg's uncertainty principle can be explained as :

• $∆$x $⩾$ $\frac{∆\mathrm{p} \times \mathrm{h}}{4\mathrm{\pi }}$

• $\mathrm{∆}$x x $∆$p $⩾$ $\frac{\mathrm{h}}{4\mathrm{\pi }}$

• $∆$x x $∆$p $⩾$ $\frac{\mathrm{h}}{\mathrm{\pi }}$

• $∆$p $⩾$ $\frac{\mathrm{\pi h}}{∆\mathrm{x}}$

The bond energy is the energy required to :

• dissociate one mole of the substance

• dissociate bond in 1 kg of the substance

• break one mole of similar bonds

• break bonds in one mole of the substance

What is binding energy in ${}_5{}^{11}\mathrm{B}$ nucleus , if mass is 0.08181 amu ?

• 1.2 x 10^-4 erg/nucleus

• 8.2 x 10^-4 erg/nucleus

• 10.2 x 10^-4 erg/nucleus

• 1.9 x 10^-4 erg/nucleus

555.

Hydrofluoric acid shows hydrogen bonding due to :

• high electron affinity of fluorine

• high bond dissociation energy of fluorine

• high electronegativity of fluorine

• none of the above

Assertion: The S-S-S bond angle in S₈ molecule is 105°.

Reason : S₈ has a V-shape.

• 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

Assertion : Sodium formate has both the C-O bonds have same value 1.27Å.

Reason : Equal bond length is due to the phenomenon of resonance.

• 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

Ionic compounds are formed most easily with :

• low electron affinity , high ionisation energy

• high electron affinity , low ionisation energy

• low electron affinity , low ionisation energy

• high electron affinity , high ionisation energy

The order of bond length is

• O₂ < O₃ < O${}_2^{2-}$

• O₂ < O${}_2^{2-}$ < O₃

• O${}_2^{2-}$ < O₃ < O₂

• O₂ = O${}_2^{2-}$ > O₃

The correct order of dipole moment is

• CH₄ <NF₃ <NH₃ <H₂O

• NF₃ <CH₄ <NH₃ <H₂O

• NH₃ <NF₃ <CH₄ <H₂O

• H₂O <NH₃ <NF₃ <CH₄