$(a)$ How is vinegar made?
$(b)$ What is glacial acetic acid? What is its melting point?
$(c)$ Why are carboxylic acids called weak acids?
$(d)$ Write the name and the formula of the two compounds formed when the ester $CH_{3}COOC_{2}H_{5}$ undergoes saponification.

(D) Vinegar is made by the fermentation of ethanol using bacteria like $Acetobacter$ $aceti$,which produces a $5-8\%$ aqueous solution of acetic acid.
$(b)$ Pure ethanoic acid (acetic acid) is known as glacial acetic acid because it freezes into an ice-like solid at temperatures below $290 \ K$.
$(c)$ Carboxylic acids are called weak acids because they do not ionize completely in an aqueous solution; they only partially dissociate into ions.
$(d)$ When the ester $CH_{3}COOC_{2}H_{5}$ (ethyl ethanoate) undergoes saponification,it reacts with a base (like $NaOH$) to form:
$1.$ Sodium ethanoate $(CH_{3}COONa)$
$2.$ Ethanol $(C_{2}H_{5}OH)$