Class 12th

8.9 The stability in aqueous condition depends on the hydration energy of the ions when they bond to the water molecules. And, the hydration energy is the amount of heat released as an ionic substance is dissolved and its constituent ions are hydrated or surrounded by water molecules.

Now, in Cu²⁺ and Cu⁺ ion, Cu²⁺ has a greater charge density than the Cu⁺ ion and so forms much stronger bonds releasing more energy. Therefore, in an aqueous medium, Cu²⁺ ion is more stable than Cu⁺ ion. This is because the energy required to remove one electron from Cu⁺ to Cu²⁺, is compensated by the high hydration energy of Cu²⁺.

Benzene into aniline

When Benzene is treated with HNO₃/H₂SO₄ it forms nitrobenzene. When Nitrobenzene reduced with Sn/HCL it forms Aniline because Sn/HCl is a reducing Mixture.

When Benzene is reacted with nitrating mixture it forms nitrobenzene. When it Reduced H₂/Pd in ethanol or Sn/HCl, it forms Aniline. When Aniline reacts 2 times with CH₃Cl It forms N, N- dimethylaniline.

When 1,4-dichlorobutane reacts with NaCN it forms Di cyanide compound, After Hydrogenation it forms the Hexane 1,6-Diamine.

5.27

Oxidation of sulphur dioxide into sulphur trioxide in the presence of

(3) Oxidation of ammonia into nitric acid in presence of platinum gauze in Ostwald's process

→ 4NH₃ (g)+ 5O₂ (g) Pt (s) 4NO +6H₂O

(4) Hydrogenation of vegetable oils in presence of Nickel as catalyst

Vegetable oil (l)+H₂ (g) Ni → Vegetable ghee (s)

8.8 Given, Z=atomic number = 27 = [Ar]3d⁷ 4s²

⇒ M²⁺ = [Ar]3d⁷

Hence, 3 unpaired electrons are present.

The spin only magnetic moment μ= √n(n+2)

Where n is the number of unpaired electrons.

Hence, μ =√(3*(3+2))

μ = √15 BM or μ = 3.87 BM

(i) & (ii) There are total 8 geometrical isomers of the given compound.

(iii) a) Pairs 1,2,6,7 Exhibit Position isomerism; means the change in position of the substituent.

b) Pairs 1,3 and 1,4 and 2,3 and 2,4 exhibit chain isomerism i.e. in this type of isomerism the different structures can be produced by changing the chain of the

c) Pairs 5,6 and 5,7 exhibit metamerism; e. different group on either side of the central atom.

d) All Primary amines exhibit functional isomers. All secondary amines share functional isomerism and same for The functional isomerism means same functional group.

8.7 The following reactions are involved when Cr²⁺ and Fe²⁺ act as reducing

Cr²⁺ = Cr3+ ( E^? _{Cr3+/ Cr2+} = - 0.41 V)

Fe²⁺⇒ Fe³⁺ (E^? _{Fe3+/ Fe2+} = +0.77 V)

Since, Cr has less potential value, Cr²⁺ gets oxidised easily than Fe²⁺. Therefore, Cr²⁺ is a better reducing agent that Fe³⁺.

(ii) Tertiary, because the Nitrogen atom is attached to the 3 carbon atoms.
(iii) Primary, because the nitrogen atom is attached to the only 1 carbon atom.
(iv) Secondary, because the nitrogen atom is attached to the only 1 carbon.

8.6 The oxidation state increases when an atom loses its Example: When Fe loses 2 electrons, its oxidation state becomes +2 from 0.

Oxygen (O) and fluorine (F) are very strong oxidizing agents. Both oxide and fluoride ions are highly electronegative and have a very small size, so they attract the electrons from metal atoms. Hence, they oxidize the metal to its the highest oxidation state.