CaO and NaCl have the same crystal structure and approximately the same ionic radii. If U is the lattice energy ofNaCI, the approximate lattice energy of CaO is

• U/2

• U

• 2U

• 4U

During the formation of a chemical bond :

• electron-electron repulsion becomes more than the nucleus-electron attraction

• energy of the system does not change

• energy increases

• energy decreases

The number of $\mathrm{\sigma }$- and $\mathrm{\pi }$-bonds present in pent-4-ene-1-yne is

• 10, 3

• 4, 9

• 3, 10

• 9, 4

544.

Assertion : H₂S is less acidic than H₂Te.

Reason : Te has larger, radius than S.

• 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 : R₃P=O exists but R₃N=O does not exist.

Reason : P is more electronegative than N.

• 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 basic structural. unit and its geometry in silicates is :

• SiO₂ , tetrahedral

• Si${\mathrm{O}}_4^{4-}$ , square planar

• SiO₂ , square planar

• Si${\mathrm{O}}_4^{4-}$ , tetrahedral

Assertion : Bond energy and bond dissociation energy have identical value for diatomic molecules.

Reason : Greater the bond dissociation energy, less reactive is the bond.

• 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.

KF combines with HF to form KHF₂. This compound contains the species

• K⁺, F^- and H⁺

• K⁺, F^- and HF

• K⁺ and [HF₂]^-

• [KHF]⁺ and F₂

The molecules having the same hybridization, shape and number of lone pairs of electrons are

• SeF₄, XeO₂F₂

• SF₄, XeF₂

• XeOF₄, TeF₄

• SeCl₄, XeF₄

The M - O- M bond angles in MO (where M is halogen) is in the order

• Br₂O > Cl₂O > F₂O

• F₂O > Br₂O > Cl₂O

• F₂O > Cl₂O > Br₂O

• Cl₂O > F₂O > Br₂O