Introduction To Organic Chemistry

The Stephan Reaction involves the substitution of a halogen (usually chlorine) in an aromatic compound with an alcohol group. This is typically achieved using a strong base like sodium hydroxide (NaOH). The general form of the Stephan reaction is: Here, chlorobenzene reacts with sodium hydroxide to form phenol (C6H5OH) and sodium chloride (NaCl). This is a classic example of a nucleophilic substitution reaction where the hydroxide ion from NaOH replaces the chlorine atom in the chlorobenzene. Therefore, option (2) represents the correct reaction.

The pH of a solution is related to the concentration of hydrogen ions ( ) by the equation: Given that the pH is 2.7, we can rearrange the equation to solve for : Calculating : However, considering significant figures and more precise calculation: Thus, the concentration of hydrogen ions is approximately .

The pH of a buffer solution is calculated using the Henderson-Hasselbalch equation: Here:
- is the negative logarithm of the acid dissociation constant ( ).
- is the concentration of the conjugate base (salt).
- is the concentration of the weak acid.
Conclusion: Use the given concentrations and to calculate the pH.

Zinc ( ) in the 3d series of transition elements exhibits a lower oxidation state. Unlike other transition elements, which commonly show variable oxidation states due to their partially filled -orbitals, zinc has a completely filled -orbital configuration.
Electronic Configuration of Zn: Since the -orbitals are fully filled, zinc typically shows an oxidation state of due to the loss of its two -electrons, which is lower compared to other elements in the 3d series. Conclusion: Zinc shows the lowest oxidation state compared to other elements in the 3d series.

Clemmensen reduction is a chemical reaction used to reduce aldehydes or ketones to alkanes. This reaction employs zinc amalgam (Zn-Hg) and concentrated hydrochloric acid (HCl) as the reducing agent. Reaction: This method is particularly suitable for compounds that are stable in strongly acidic conditions.
Conclusion: Clemmensen reduction involves the reduction of aldehydes and ketones to alkanes using zinc amalgam and HCl.

The molecular formula corresponds to an alcohol with three carbon atoms, making it propanol. The functional group confirms it is an alcohol. Thus, the correct IUPAC name for the compound is propanol, corresponding to option (3).

The molecular formula corresponds to an alcohol with two carbon atoms, indicating it is ethanol. The functional group confirms it is an alcohol. Thus, the correct IUPAC name is Ethanol. Therefore, the correct answer is option (2).