Question

Which of the following dissolves in water
A.Wood
B. Jaggery
C. Dust
D. An eraser

Answer 1

Hint: The substance which dissolves in water must settle between the molecules of the water. If a substance cannot settle between the molecules of water then it is not soluble in water. For this settling process, it must be broken into fine particles and remain stable with water. Also there must be attraction between the added substance and water molecules.

Complete answer: Whenever we add a substance to any solvent then it will be soluble in the solvent only when its particles settle between the molecules of the solvent. On adding wood, dust and an eraser to water solvent we get a heterogeneous solution. Even wood and erasers float above the water. Dust particles can be seen in the water as they are not soluble in water. But Jaggery is a form of sugar which is soluble in water. When we add jaggery to water then its particles break down and get settled between the molecules of water and form a stable solution. Also sugar contains hydroxyl groups which makes it polar in nature. Thus it is soluble in water. Therefore we can say that jaggery is soluble in water.
Hence the correct answer is option B.

Note:
We know that like dissolves like which means that sugar being polar in nature dissolves in polar solvent like water. Also on increasing the temperature of water the solubility of jaggery increases. Jaggery is also a form of sugar and contains polar groups like sugar contains. If we crush the particles of jaggery and then add it to water then it is more easily soluble as jaggery particles can easily get settled between the particles of water.