Explanation:
Part a
Pyridine is an aromatic heterocyclic compound and undergoes nucleophilic aromatic substitution reaction at 2 and 4 positions.
This is because, when a nucleophile attack pyridine at 2 and 4 positions, the anoin formed is stabilized. In the anion formed is tabilized by resonance and also negative charge is present at electronegative atom, nitrogen.
If the nucleophile attack at 3 position, the anion formed is not as stable as anions formed when nucleophile attach at 2 and 4 positions. This is because negative charge is not present at the nitrogen atom.
Part b:
Tautomers are structural isomers of each others formed by migration atom within the molecule. Tautomers exist in equilibrium with each other.
Tautomers of 2-Hydroxypyridine and 4-Hydroxypyrine are given in the attachment.
Answer:
In crystal structure close packing is define as space efficient arrangement of constituent particles to form a crystal lattice.
Explanation:
closest packing
In crystal structure close packing is define as space efficient arrangement of constituent particles to form a crystal lattice.
Difference between hexagonal closest packing and cubic closest packing
In cubic closest packing arrangement, each sphere is surrounded by 12 other spheres on the other hand in case of hexagonal close packing, layers of spheres are packed so that spheres in alternating layers overlie one another.
unit cell for each closest packing arrangement
The hexagonal closest packed arrangement has a coordination number of 12 and it consists of 6 atoms per unit cell. The face centered cubic lattice has a coordination number of 12 and it consists of 4 atoms per unit cell. In case of body centered cubic crystal the coordination number is 8 and it consists of 2 atoms per unit cell.
C).dd offspring have a nice day
