Question

Which of the following is insoluble in $AcOH$ ?
A.Calcium oxide
B.Calcium carbonate
C.Oxalates
D.Calcium hydroxide

Answer 1

Hint: $AcOH$ is a symbol for acetic acid also known as ethanoic acid, where $Ac$ is the pseudo element for acetyl group. It is a weak acid with a pungent smell and is soluble in water. Oxalate ions are soluble in strong acids as oxalic acid is a strong acid.

Complete Answer:
$AcOH$ is a symbol for acetic acid. Here, $Ac$ represents the acetyl group, $C{H_3}C = O$ . Acetic acid or ethanoic acid is a colourless liquid with pungent smell which when not diluted is known as glacial acetic acid and has the chemical formula $C{H_3}COOH$ . It is a nonpolar protic solvent which is moderately a weak acid. It is readily soluble in water because it forms hydrogen bonds with water and dissociates to acetate and ${H^ + }$ ions thus it is easily soluble in water but is a weak electrolyte.
Acetic acid is a dangerous chemical for skin. It is highly corrosive to the skin and eyes and can also cause damage to internal organs if inhaled. It is used as a solvent and in textile industries, for photographic films and for production of various materials like plastics and other acetates. 10% acetic acid is vinegar which is used in food products.
According to the given question, calcium oxide, calcium carbonate and calcium hydroxide are soluble in acetic acid whereas oxalates are not soluble in weak acids and are soluble only in strong acids and acetic acid is a weak acid, therefore, oxalate ions ${C_2}{O_4}^ - $ are not soluble in $AcOH$ . The oxalate ions are insoluble in acetic acid due to their high lattice energy.

Thus, the answer for the given question is option (C) oxalates.

Note: Carboxylic acids are an important functional group. They contain the carboxyl group $ - COOH$ . Primary alcohols and aldehydes are oxidised with the help of an oxidising agent to yield carboxylic acids. Methanoic acid is used in textile, rubber and dying industries and Hexanoic acid is used to manufacture polymers.