Chemical Bonding and Atomic Structure MCQs for NEET — Chemistry Questions with Answers

(d) According to the postulate of VSEPR theory, a lone pair occupies more space than a bonding pair, since it lies closer to the central atom. This means that the repulsion between the different electron pairs follow the order.

               lp-lp>lp-bp>bp-bp

$$\begin{gathered} \left(\mathrm{c}\right) \mathrm{Hybridisation}=\frac{\mathrm{Number} \mathrm{of} \mathrm{\sigma }- \mathrm{electrons}}{2} \\ = \frac{2+2 (\mathrm{negative} \mathrm{ion})}{2} = 2=sp \end{gathered}$$

Hence, in the carbanion CH3C$\equiv$C$°$, pair of electron as (-)ve charge is present in sp-hybridised-orbital.

(a) As the number of lone pair of electrons on central element increases, repulsion between those lone pair of electrons increases and therefore, bond angle decreases.
          Molecules                            Bond angle
CH₄ (no lone pair of electrons)           109.5°
NH₃ (one lone pair of electrons)         107.5°
H₂O (two lone pair of electrons)         104.45

(a) Order of stability $\propto$ bond order

$\therefore$ Order of the stability of given species.

                     ${\mathrm{O}}_2^{+} > {\mathrm{O}}_2 > {\mathrm{O}}_2^{-} > {\mathrm{O}}_2^{2-}$

Bond order     2.5     2      1.5      1

Since, HCl is strong acid and dissociates completely. Hence, it conducts electricity best in its aqueous solution.

(c) The compounds with lower oxidation number and which cannot reduced by one another can exist together. Thus, FeCl₂ and SnCl₂ can exist together as Fe²⁺ cannot be reduced by Sn²⁺

Among the given options, NH3 (ammonia) has the maximum dipole moment. Dipole moment arises due to the asymmetric distribution of charge in a molecule. NH3 has a pyramidal shape with a lone pair of electrons, making it polar. CO2 and CH4 are non-polar due to their symmetric structure.