Viraf J. Dalal solutions for Simplified ICSE Chemistry [English] Class 9 chapter 3 - Water [Latest edition]

Name one substance which is ‘deliquescent’.

How does an increase in temperature affect the solubility of NaCl?

How does an increase in temperature affect the solubility of CaSO₄ in water?

Give reason for white power forms on the surface of washing soda crystals which are left exposed to the air.

Give reason for Table salt becomes moist during rainy season.

Name a salt which does not contain water of crystallization.

Name a salt which contain of crystallization.

Name a deliquescent substance’.

Explain the following observation:

In the expression anhydrous copper sulphate, what is meant by “anhydrous”?

Explain the following observation:

Why is fused calcium chloride or cone, sulphuric acid used in a desiccator?

Explain the following observation:

Washing-soda become coated with a white powder when left exposed to the atmosphere.

Complete the following:

The solubility of a gas at constant pressure may be increased by decreasing the

What is ‘water of crystallization’ ? Name a crystalline salt which does not contain water of crystallization.

What would you observe, when the water of crystallization of a salt Is removed by heating it.

Define the following term: Hygroscopy.

Define the following term: Efflorescence.

What is the effect of temperature on the solubility of KNO, and calcium sulphate in water?

What test would you do to find out whether a given solution is saturated or unsaturated.

How can you increase the solubility of a given volume of gas in water?

Define ‘eutrophication’.

What is meant by the term ‘oil spill’.

State any two sources of water pollution.

State the causes and consequences of ‘eutrophication’.

What is meant by the term ‘offshore drilling’. State the main environmental effects of offshore drilling.

Explain why oil spills have an adverse effect on marine life.

Explain any two environmental impacts of an ‘oil spill’.

Explain the methods of controlling water pollution.

State the importance of water for all general uses.

How does it occur in the free state and in the combined state.

State a reason to prove that water is a compound and not a element.

State why ‘Water is considered a universal solvent’. Give the reason for the same.

Define the term – solute

Define the term – solvent

Define the term solution.

State the characteristics of a true solution.

Differentiate between unsaturated, saturated & supersaturated solutions.

How would you convert a saturated solution to an unsaturated solution and vice versa?

Define solubility. Give the main steps with the calculations involved of the method to determine the solubility of a given salt ‘X’ in water.

From the following list of salts: Na₂SO₄, 10H₂O, NaCl, KClO₃, NaNO₃, Ca(OH)₂, NH₄Cl, KCI, CaSO₄.

State the salts whose solubility increases with a rise in temperature of the water.

From the following list of salts: Na₂SO₄, 10H₂O, NaCl, KClO₃, NaNO₃, Ca(OH)₂, NH₄Cl, KCI, CaSO₄.

State the salts whose solubility decreases with a rise in temperature of the water.

From the following list of salts: Na₂SO₄, 10H₂O, NaCl, KClO₃, NaNO₃, Ca(OH)₂, NH₄Cl, KCI, CaSO₄.

State the salts whose solubility is fairly independent or slightly increases with a rise in temperature of the water.

What is a solubility curve. State two applications and two benefits of the solubility curve.

Give the influence of pressure.

Give the influence of temperature on the solubility of gases in water.

State the reason why boiled water tastes flat.

State the reason why a soda water bottle opens with a ‘fizz’.

What is meant by the term crystal?

What is meant by the term crystallization?

What is meant by the term seed crystal.

Define the term ‘water of crystallization’.

Differentiate between hydrated and anhydrous crystals with examples. State three defined changes that occur when hydrated copper sulphate is heated.

Washing soda and iron [III] chloride are separately exposed to the atmosphere. State

1. the observations seen
2. the phenomenon which occurs
3. the reason for the phenomenon occurring in each case.

Would a similar phenomenon occur in case of exposure of common salt. Explain giving reasons.

Why is fused calcium chloride and not potassium chloride kept in a desiccator?

How does fused calcium chloride differ from iron [III] chloride when exposed to the atmosphere?

Cone H₂SO₄ acts as a ‘drying agent’ & a ‘dehydrating agent’. Explain and differentiate the words in italics.

Explain the meaning of the terms – hard water & soft water.

State the causes of hardness in water.

Give two natural sources of hard water.

Differentiate between Temporary & permanent hard water with suitable examples.

What causes the temporary and permanent hardness of water?

State the disadvantages of using hard water.

Give reason for the following:

Hardness in temporary water can be removed by boiling, but hardness in permanent hard water cannot.

Give balanced equation to show how temporary hardness in water can be removed by boiling.

Both temporary & permanent hardness in water can be removed by addition of washing soda. Give balanced equations for the same.

A sample of water is given in a trough. State how would you prove experimentally whether the given sample is hard water or soft water.

Two samples of water are placed in a beaker individually. State how you will determine experimentally which of the two samples contains permanent hard water.

State what are synthetic detergents. Explain experimentally how you will determine the advantage of synthetic detergents over soap using a sample of hard water.

Select the correct word from the words in option to complete the sentence:

If pressure on the surface of water increases its boiling point ____ and freezing point ____.

Select the correct word from the words in option to complete the sentence:

A saturated solution can be converted to an unsaturated solution by ____ the amount of the solvent.

Select the correct word from the words in option to complete the sentence:

Dissolved air in water contains a ____ percentage of oxygen than ordinary air.

Select the correct word from the words in option to complete the sentence:

At low temperatures, the solubility of a gas in water is ____ compared to that at ordinary temperatures.

Select the correct word from the words in option to complete the sentence:

Efflorescence occurs when the vapour pressure of the hydrated crystals is ____ than the vapour pressure of the atmospheric humidity.

Select the correct answer from the choice given in the options.

An anhydrous crystal _____.

Select the correct answer from the choice given in the options.

A substance which causes hardness in water _____.

Select the correct answer from the choice given in the options.

A deliquescent salt of a divalent metal _____.

Select the correct answer from the choice given in the options.

An anhydrate of a heptahydrate salt _____.

Select the correct answer from the choice given in the options.

A drying agent, deliquescent in nature used in a dessicator ______.

Give reason for the following:

Solubility curves find utility in separation and purification of solutes.

Give a reason for the following:

Pressure and temperature influence the solubility of gases in water.

Give a reason for the following:

Heating a hydrated copper sulphate crystal is deemed a chemical change.

Give a reason for the following:

Efflorescence is minimum during humid conditions.

Give a reason for the following:

A crusty ‘boiler scale’ is formed in boilers, when hard water is used.

Name or state the following:

An efflorescent decahydrate salt.

Name or state the following:

A deliquescent salt of a trivalent metal.

Name or state the following:

A liquid hydroscopic substance.

Name or state the following:

A salt whose solubility decreases with rise in temperature of the solvent water.

Name or state the following:

A substance added to remove both temporary and permanent hardness in water.

Differentiate between the following:

Natural water and treated water

Differentiate between the following:

Saturated solution and a supersaturated solution

Differentiate between the following:

Solubility and solubility curve

Differentiate between the following:

Deliquescent salt and hygroscopic salt

Differentiate between the following:

Solute and solvent – forming a solution.

Match the terms in List I with the correct answers in List II.