Assertion : $\mathrm{}\mathcal{}$ F bond angle P = bond angle Q but not precisely $90°.$

Reason : The molecule is slight bent T-shaped and there is repulsion between lone pairs of electrons.

1. If both the assertion and the reason are true and the reason is a correct explanation of the assertion
2. If both the assertion and reason are true but the reason is not a correct explanation of the assertion
3. If the assertion is true but the reason is false
4. If both the assertion and reason are false

Assertion : ${\mathrm{N}}_2{{\mathrm{F}}_3}^{+}$ is planar at each nitrogen atom.

Reason : ${\mathrm{N}}_3\mathrm{H},$ the bond angle $\mathrm{H}‐\mathrm{N}‐\mathrm{N}$ is $120°$ and both the $\mathrm{N}‐\mathrm{H}$ bond lengths are not equal.

Assertion : Carbon has unique ability to form $\mathrm{p\pi }-\mathrm{p\pi }$ multiple bonds with itself and with other

                  atoms of small size and high electronegativity.

Reason : Heavier elements of group ${14}^{\mathrm{th}}$ do not form $\mathrm{p\pi }-\mathrm{p\pi }$ multiple bonds with itself because

               their atomic orbitals are too large and diffuse to have effective overlapping.

Assertion : ${\mathrm{NO}}^{+}$ and ${\mathrm{CN}}^{-}$ both have same bond order and magnetism

Reason : ${\mathrm{NO}}^{+}$ and ${\mathrm{CN}}^{-}$ are isoelectornic species.

Assertion : Crystals of hydrated calcium sulphate $\left(\mathrm{gypsum} : {\mathrm{CaSO}}_4, 2{\mathrm{H}}_2\mathrm{O}\right)$ are soft and easily cleaved.

Reason : Crystals of anhydrous calcium sulphate $\left(\mathrm{anhydrite} : {\mathrm{CaSO}}_4\right)$ are very hard and very difficult

               to cleave.

 When two atoms combine to form a molecule, energy is: 

A compound having the Highest Melting Point :

1. BeCl₂

2. MgCl₂

3. CaCl₂

4. SrCl₂

The diamagnetic species among the following is:

1. NO

2. CO

3. O₂

4. B₂

Which of the statements are not true for AlCl₃-

1. AlCl₃ fumes in moist air forms HCl with moisture

2. Anhydrous AlCl₃ exists as Al₂Cl₆

3. Anhydrous AlCl₃ is ionic

4. Anhydrous AlCl₃ is trigonal planar molecule at higher temperature

Valency is best described as:

1. Total electrons in an atom

2. Atomicity of an element

3. Oxidation number of an element

4. Combining capacity of an element