$$-F$$  is a strong electron withdrawing group. Electron withdrawing group present nearer to the $$-COOH$$  group has more acidic strength, hence low $$p{K_a}$$  value.

Carbonylic acids reacts with $$C{l_2}$$  or $$B{r_2}$$  in presence of red $$P$$ to give exclusively $$\alpha $$ - chloro or $$\alpha $$ - bromo acids. This reaction is called Hell-Volhard-Zelinsky $$(HVZ)$$  reduction. This reaction is example of $$\alpha {\text{ - }}H$$ - substitution.

Higher carboxylic acids are practically insoluble in water due to the increased hydrophobic interaction of hydrocarbon part. Thus, decanoic acid is highly insoluble in water.

The optically active acid will react with $$d$$  and $$l$$  forms of alcohol present in the racemic mixture at different rates to form two diastereomers in unequal amounts leading to optical activity of the product.

Carboxylic acid is stronger acid than phenol. The presence of electron withdrawing group $$\left( {e.g\,\,Cl} \right)$$   increases acidic strength, while presence of electron donating group $$\left( {e.g\,\,C{H_3}} \right)$$   decreases acidic strength.

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\[\beta -\]  Keto acids are decarboxylated by following mechanism

\[\left( A \right)\,Ph-C{{H}_{2}}-Br\xrightarrow{KCN}\]      \[Ph-C{{H}_{2}}-C\equiv N\xrightarrow{{{H}_{3}}{{O}^{+}}}\]      \[Ph-C{{H}_{2}}-C{{O}_{2}}H\left( B \right)\]

Ethane is obtained by the electrolysis of sodium or potassium salt of ethanoic acid \[\left( C{{H}_{3}}COOH \right),\]   hence the ester must be ethanoate \[C{{H}_{3}}COOR.\]

The given reaction is Rosenmund reaction