which of the following substances is completely insoluble in water?\na limestone\nb vinegar\nc oil\nd two of…

Answer:

C. oil

Explanation:

Step1: Analyze limestone

Limestone (calcium carbonate) is sparingly - soluble in water due to the presence of carbonate ions that can react with water and acidic substances in water to a small extent.

Step2: Analyze vinegar

Vinegar is an aqueous solution of acetic acid and water - soluble substances. It is miscible in water as it is a polar substance and water is also a polar solvent.

Step3: Analyze oil

Oil is a non - polar substance. Water is a polar substance. According to the principle of "like dissolves like", non - polar oil is completely insoluble in polar water. So oil is the substance that is completely insoluble in water among the options.