Complete the following table. Common Name Chemical Name Formula Acid, base, or salt Efflorescent, hygroscopic, or deliquescent substance Solid caustic potash Quicklime Oil of vitriol Washing soda Solid caustic soda Blue vitriol

There are substances that absorb water when exposed to the atmosphere, become moist and lose their crystalline form. They are called deliquescent substances. An example is a caustic potash. Its chemical name is potassium hydroxide with a chemical formula KOH . It is a base. Certain substances absorb moisture (water vapour) from the atmosphere without dissolving in it. Such substances are called hygroscopic substances. Quick lime is an example of this. It is a base with chemical name calcium oxide and chemical formula CaO . Certain substances absorb moisture (water vapour) from the atmosphere without dissolving in it. Such substances are called hygroscopic substances. Oil of vitriol is an example of this. It is an acid with a chemical name sulphuric acid and a chemical formula H 2 SO 4 . Substances that lose water of crystallisation when exposed to air are called efflorescent substances. Washing soda is an example of this. It is a salt with a chemical name sodium carbonate decahydrate and a chemical formula Na 2 CO 3 . 10 H 2 O . There are substances that absorb water when exposed to the atmosphere, become moist and lose their crystalline form. They are called deliquescent substances. Solid caustic soda is an example of this. It is a base with a chemical name sodium hydroxide and a chemical formula NaOH . Substances that lose water of crystallisation when exposed to air are called efflorescent substances. Blue vitriol is an example of this. It is a salt with a chemical name Copper sulphate and a chemical formula, CuSO 4 . Common Name Chemical Name Formula Acid, base, or salt Efflorescent, hygroscopic, or deliquescent substance Solid caustic potash Potassium hydroxide KOH Base Deliquescent substance Quicklime Calcium oxide CaO Base Hygroscopic Oil of vitriol Sulphuric acid H 2 SO 4 Acid Hygroscopic Washing soda Sodium carbonate decahydrate Na 2 CO 3 . 10 H 2 O Salt Efflorescent substance Solid caustic soda Sodium hydroxide NaOH Base Deliquescent substance Blue vitriol Copper sulphate CuSO 4 Salt Efflorescent substance

In which of the following substances will there be an increase in mass when they are exposed to air? Sodium chloride Iron Conc. sulphuric acid Table salt Sodium carbonate crystals

Iron reacts with the oxygen from the air to make iron oxide or rust. So the weight increases in case of iron. This process is called as corrosion or rusting of iron. Concentrated sulphuric acid increases in weight when exposed to air because concentrated sulphuric acid has strong affinity for water and is hygroscopic. It readily absorbs moisture.

In which of the following substances will there be no change in mass when they are exposed to air? Sodium chloride Iron Conc. sulphuric acid Table salt Sodium carbonate crystals

Table salt or sodium chloride does not increase or decrease in mass because when table salt is left exposed to air, it tends to absorb moisture from the air and convert it into liquid, but there is no change in mass. This is because table salt contains impurities like magnesium chloride which are deliquescent.

E M B I B E

Concise Chemistry Class 9>Chapter 3 - Water>EXERCISE 3(B)

S P Singh Solutions for Chapter: Water, Exercise 2: EXERCISE 3(B)

Author:S P Singh

S P Singh Chemistry Solutions for Exercise - S P Singh Solutions for Chapter: Water, Exercise 2: EXERCISE 3(B)

Attempt the practice questions on Chapter 3: Water, Exercise 2: EXERCISE 3(B) with hints and solutions to strengthen your understanding. Concise Chemistry Class 9 solutions are prepared by Experienced Embibe Experts.

Questions from S P Singh Solutions for Chapter: Water, Exercise 2: EXERCISE 3(B) with Hints & Solutions

MEDIUM

9th ICSE

IMPORTANT

Concise Chemistry Class 9>Chapter 3 - Water>EXERCISE 3(B)>Q 14

Normally, the solubility of a crystalline solid increases with temperature. Does it increase uniformly in all the cases? Name a substance whose solubility increases slightly with temperature.

MEDIUM

9th ICSE

IMPORTANT

Concise Chemistry Class 9>Chapter 3 - Water>EXERCISE 3(B)>Q 14

Normally, the solubility of a crystalline solid increases with temperature. Does it increase uniformly in all the cases? Name a substance whose solubility initially increases and then decreases with rise in temperature.

MEDIUM

9th ICSE

IMPORTANT

Concise Chemistry Class 9>Chapter 3 - Water>EXERCISE 3(B)>Q 15

What are drying or desiccating agents? Give examples.

HARD

9th ICSE

IMPORTANT

Concise Chemistry Class 9>Chapter 3 - Water>EXERCISE 3(B)>Q 16

Complete the following table.

Common Name	Chemical Name	Formula	Acid, base, or salt	Efflorescent, hygroscopic, or deliquescent substance
Solid caustic potash
Quicklime
Oil of vitriol
Washing soda
Solid caustic soda
Blue vitriol