Ncert Solutions Chemistry Class 11th

3.46. (b) Electronegativity refers to the tendency of an atom to share electrons with another atom.

Anhydrous Ferric Chloride (FeCl₃) is another Lewis acid which can be used during ethylation of benzene.

CH₃ group is electron-donating while -NO₂ group is electron-withdrawing. Therefore, maximum electron density will be in toluene, followed by benzene and least in m-dinitrobenzene. Therefore, the ease of nitration decreases in the order: toluene > benzene > m-dinitrobenzene.

3.45.  (b) It has only ones-electron and hence can be placed in group 1 (alkali metals). It can also gain an electron to achieve a noble gas arrangement and hence it can behave similarly to a group 17 (halogen family) element. Because it is a special case, we shall place hydrogen separately at the top of the Periodic Table

The basic skeleton structure of 2-methylbutane is

Placing double bonds at different positions and satisfying the tetra covalency of each carbon, the structures of various alkenes which give 2-methylbutane on hydrogenation are: 

Benzene is a rich source of electrons because of the presence of an electron cloud containing 6 n-electrons above and below the plane of the ring. Consequently, it attracts the electrophiles (electron-deficient) reagents towards it and repels nucleophiles (electron- rich) reagents. As a result, benzene undergoes electrophilic substitution reactions easily and nucleophilic substitutions with difficulty.

3.44.  (d) Assertion is a wrong statement. Non-metallic elements have a strong tendency to gain electrons. Therefore, electronegativity is directly related to those non-metallic properties of elements. It can be further extended to say that the electronegativity is inversely related to the metallic properties of elements.

Thus, the increase in electronegativities across a period is accompanied by an increase in non-metallic properties (or a decrease in metallic properties) of elements

The hybridization state of carbon in these three compounds is:

Since s-electrons are closer to the nucleus, therefore, as the s-character of the orbital making the C—H bond increases, the electrons of C—H bond lie closer and closer to the carbon atom. In other words, the partial +ve charge on the H-atom and hence the acidic character increases as the s-character of the orbital increases. Thus, the acidic character decreases in the order: Ethyne > Benzene > Hexane.