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.
The main constituent of gallstones is cholesterol. Cholesterol may have a role in heart attacks and blood clot formation. Its elemental percentage composition is 83.87% C, 11.99% H, and 4.14% O. It has a molecular weight of 386.64 amu. Empirical formula is C₃H₄O₁ and Molecular formula is 7(C₃H₄O₁).
<h3>What is Empirical Formula ?</h3>
Empirical formula is the simplest whole number ratio of atoms present in given compound.
Element % Atomic mass Relative no. of atoms Simplest whole ratio
C 83.87 12
= 6.98
= 3
H 11.99 1
= 11.09
= 4
O 4.14 16
= 0.25
= 1
Thus the empirical formula is C₃H₄O₁.
<h3>How to find the Molecular formula of compound ?</h3>
Molecular formula = Empirical formula × n
n = 
= 
= 7
Molecular formula = Empirical formula × n
= 7 (C₃H₄O₁)
Thus from the above conclusion we can say that The main constituent of gallstones is cholesterol. Cholesterol may have a role in heart attacks and blood clot formation. Its elemental percentage composition is 83.87% C, 11.99% H, and 4.14% O. It has a molecular weight of 386.64 amu. Empirical formula is C₃H₄O₁ and Molecular formula is 7(C₃H₄O₁).
Learn more about the Empirical Formula here: brainly.com/question/1603500
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Answer:
Avogadro's number is the number of particles in one mole of anything. In this context, it is the number of atoms in one mole of an element. It's easy to find the mass of a single atom using Avogadro's number. Simply divide the relative atomic mass of the element by Avogadro's number to get the answer in grams.