Lewis acid is any substance that can accept a pair of non- bonding electrons, such as the H⁺ ions. It is an electron pair acceptor.

Lewis base is any substance that can donate a pair of electrons.

OH^-, F^- and NH₃ are Lewis base because they can donate a lone pair of electrons while H⁺ is a Lewis acid because it can accept a lone pair of electrons.

In the reaction, two moles of C-H bonds and two moles of C-Cl bonds are broken. Hence, energy absorbed is

 = 2 x 416 + 2 x 325

 = 1482kJ

CaC₂ and H₂O reacts to produce C₂H₂ (acetylene gas).

CaC₂(s) + 2H₂O(l) $\to$ Ca(OH)₂(aq) + C₂H₂

-NH₂, -OH and -R (alkyl groups) all are o/p- directing and they activates the benzene ring -(X) halogens are however o/p-directing but deactivate the benzene ring by withdrawing electrons fron the ring due to -I effect.

If both nitrogen and sulphur are present in a organic compound, they will give red blood colour with Lassaigne test due to the formation of ferric thiocyanate.

Na + C + S + N $\stackrel{∆}{\to }$ NaSCN (sodium thiocyanate)

Fe³⁺ + 3NaSCN $\to$Fe(SCN)₃ + 3Na⁺

                            ferric thiocyanate

Electronegativity, ionisation energy and electron affinity of s-block elements in their respective period is low but the atomic radius of the s-block elements is larger in their respective period due to less effective nuclear charge.

B₃N₃H₆ (borazine) is known as inorganic benzene. Borazine is isoelectronic, i.e. same number of electrons and isosteric, i.e. same number of atoms with benzene.

Ammonia is dried over quick lime (CaO). It cannot be dried over conc. H₂SO₄, P₂O₅ and CaCl₂ because it reacts with these compounds.

IUPAC name of the above compound is 3-methylpent-3-en-2-ol

${\mathrm{\mu }}_{\mathrm{cal}}$= e x d = 1.6 x 10^-19 x 2.29 x 10^-10

     = 3.664 x 10^-29 C-m

% ionic character = $\frac{{\mathrm{\mu }}_{\exp }}{{\mathrm{\mu }}_{\mathrm{cal}}} = \frac{6.226 \mathrm{x} {10}^{-30}}{3.664 \times {10}^{-29}} \times 100$

                           = 17%