Water Exe-3C Structured Answer Chemistry Class-9 ICSE Selina Publishers

Water Exe-3C Structured Answer Chemistry Class-9 ICSE Selina Publishers Solutions Chapter-3. Step By Step ICSE Selina Concise Solutions of Chapter-3 Water with All Exercise including MCQs, Very Short Answer Type, Short Answer Type, Long Answer Type, Numerical and Structured/Application Questions Solved . Visit official Website CISCE for detail information about ICSE Board Class-9.

Water Exe-3C Structured Answer Chemistry Class-9 ICSE Concise Selina Publishers

Board ICSE
Publications Selina Publication
Subject Chemistry
Class 9th
Chapter-3 Water
Book Name Concise
Topics Solution of (Soft and hard Water) Exercise – 3C Structured/Application/Skill Answer
Academic Session 2023-2024

Exercise – 3C Structured/Application/Skill Answer Type

Water Class-9 Chemistry Concise Solutions  

Page-55

Question 1.

The following figure shows the solubility curves of NaCl, KNO3 and hydrated calcium sulphate.

The following figure shows the solubility curves of NaCl, KNO3 and hydrated calcium sulphate.

(a) Identify and label the curves with the salt it represents.

(b) State the factors on which the solubility depends.

(c) Solubility of which salt(s) shows :

(i) Endothermic process

(ii) Exothermic process?

Answer:

(a) The labelled curves are shown below:

The following figure shows the solubility curves of NaCl, KNO3 and hydrated calcium sulphate.

(b) Solubility of a solid in a solvent depends on the following factors:

  • Size of solute particles — The smaller the size of the solute particles, the greater is its total surface area exposed to the solvent. Therefore, greater is the solubility of that solute.
  • Stirring — This brings more of the solvent in contact with the solute and thus increases the rate of formation of solution.
  • Temperature — The solubility of a gas in a liquid always decreases with rise in temperature. But the solubility of most solids in water usually increases with rise in temperature.

In case of NaCl, solubility increases only a little with increase in temperature.

In case of KNO3, solubility increases considerably with increase in temperature.

In case of calcium sulphate, solubility decreases (after attaining a certain temperature) with further rise in temperature.

(c)

(i) In an endothermic process, the solubility of a solute increases with an increase in temperature.

For example: solubility of KNO3 increases with rise in temperature and solubility of NaCl increases only a little with increase in temperature.

(ii) In an exothermic process, the solubility increases on lowering the temperature.

For example: solubility of calcium sulphate in water decreases on increasing the temperature.

—  : End of Water Exe-3C Structured Answer Class-9 ICSE Chemistry Solutions :–

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