Samacheer Kalvi 10th Science Solutions Chapter 9 Pdf

Tamilnadu Board Samacheer Kalvi 10th Science Solutions Chapter 9: Tamilnadu State Board Solution Class 10 Science Chapter 9 – Solutions.

Samacheer Kalvi 10th Science Solutions Chapter 9: Overview

Board	Samacheer Kalvi
Class	10
Subject	Science
Chapter	9
Chapter Name	Solutions

Samacheer Kalvi 10th Science Solutions Chapter 9 Solutions

I.) Choose the correct answer.

1.) A solution is a __________ mixture.

a.) homogeneous

b.) Heterogeneous

c.) homogeneous and heterogeneous

d.) non-homogeneous

Ans:a.) homogeneous

Because, solution is the homogenous mixture of substances.

2.) The number of components in a binary solution is __________

a.) 2

b.) 3

c.) 4

d.) 5

Ans:a.) 2

Because, binary solution is formed from two components.

3.) Which of the following is the universal solvent?

a.) Acetone

b.) Benzene

c.) Water

d.) Alcohol

Ans:c.) Water

Because, most of the substances are dissolve in water.

4.) A solution in which no more solute can be dissolved in a definite amount of solvent at a given temperature is called _______

a.) Saturated solution

b.) Un saturated solution

c.) Super saturated solution

d.) Dilute solution

Ans: a.) saturated solution

5.) Identify the non-aqueous solution.

a.) sodium chloride in water

b.) Glucose in water

c.) copper sulphate in water

d.) sulphur in carbon-di-sulphide

Ans:d.) sulphur in carbon-di-sulphide

6.) WhenWhen pressure is increased at constant temperature the solubility of gases in liquid ___________.

a.) Nochange

b.) Increases

c.) decreases

d.) no reaction

Ans:b.) Increases

Because, with increase in pressure the solubility of gas in liquid increases, if temperature is kept constant.

7.) Solubility of NaCl in 100 ml water is 36 g. If 25 g of salt is dissolved in 100 ml of water how much more salt is required for saturation _____________.

a.) 12g

b.) 11g

c.) 16g

d.) 20g

Ans:b.) 11g

8.) A 25% alcohol solution means

a.) 25 ml alcohol in 100 ml of water

b) 25 ml alcohol in 25 ml of water

c) 25 ml alcohol in 75 ml of water

d.) 75 ml alcohol in 25 ml of water

Ans:c.) 25 ml alcohol in 75 ml of water

9.) Deliquescence is due to __________

a.) Strong affinity to water

b.) Less affinity to water

c.) Strong hatred to water

d.) Inertness to water

Ans:a.) Strong affinity to water

10.) Which of the following is hygroscopic in nature?

a.) Ferric chloride

b.) coppercopper sulphate penta hydrate

c.) silica gel

d.) none of the above

Ans:c.) silica gel

II.) Fill in the blanks

1) The component present in lesser amount, in a solution is called _______

Ans:The component present in lesser amount, in a solution is called solute.

2) Example for liquid in solid type solution is _____

Ans: Example for liquid in solid type solution is sodium chloride dissolved in water.

3) Solubility is the amount of solute dissolved in _____ g of solvent.

Ans:Solubility is the amount of solute dissolved in 100 g of solvent.

4) Polar compounds are soluble in _____ solvents

Ans:Polar compounds are soluble in polar solvents

5) Volume percentage decreases with increases in temperature because _____

Ans:Volume percentage decreases with increases in temperature because of expansion of liquid.

III.) Match the following

Ans:

1) Blue vitriol: CuSO₄.5H₂O

2) Gypsum: CaSO₄.2H₂O

3) Deliquescence: NaOH

4) Hygroscopic: CaO

IV.) True or False: (If false give the correct statement)

1) Solutions which contain three components are called binary solution.

Ans: False:

Correct statement: The solution which is made from one solute and one solvent only i.e. from two components is called as binary solution.

2) In a solution the component which is present in lesser amount is called solvent.

Ans: False

Correct statement: In a solution the component which is present in lesser amount is called solute.

3) Sodium chloride dissolved in water forms a non-aqueous solution.

Ans: False

Correct statement: Sodium chloride dissolved in water forms a aqueous solution.

4) The molecular formula of green vitriol is MgSO4.7H2O

Ans: False

Correct statement: The molecular formula of green vitriol is FeSO4.7H2O

5) When Silica gel is kept open, it absorbs moisture from the air, because it is hygroscopic in nature

Ans: True

V.) Short answer

1.) Define the term: Solution

Ans:

Solution:

Solution is the homogeneous mixture of two or more substances. The substance which is present in lesser amount by weight is called as solute and the substance which is present in larger amount by weight is called as solvent.

2.) What is mean by binary solution?

Ans:

Binary solution:

To form the solution the two substances are compulsory to mix. The solution which is made from one solute and one solvent only is called as binary solution.

For example: When copper sulphate crystals are added to water, it dissolves in water and forms the copper sulphate solution. That means it contains solute as a copper sulphate and solvent as water.

3.) Give an example each

Ans:

i) Gas in liquid:

Carbon dioxide dissolved in water (Soda water)

ii) Solid in liquid:

Sodium chloride dissolved in water.

iii) Solid in solid:

Copper dissolved in gold (Alloys)

iv) Gas in gas:

Mixture of Helium- Oxygen gases.

4.) What is aqueous and non-aqueous solution? Give an example.

Ans:

Aqueous solutions:

The solutions in which water is a solvent are called as aqueous solutions.
For example: Common salt in water, Sugar in water, Copper Sulphate in water etc.

Non-aqueous solutions:

The solutions in which any liquid other than water is used as solvent is called as non-aqueous solution.
For example: alcohols, benzenes, ethers, carbon-disulphides, acetone etc. are used as solvent in non-aqueous solutions.

6) Define Volume percentage

Ans:

Volume percentage:

It is defined as the percentage by volume of solute in ml present in the given volume of solution.
And it is given by,
Volume percentage = (volume of the solute/ volume of the solution) * 100
Volume % = (volume of the solute/ volume of the solute + volume of the solvent)* 100

7) The aquatic animals live more in cold region why?

Ans:

Because, the oxygen O₂ is more soluble in water at low temperature than the higher temperature.

In cold region, the O₂ dissolve in more amount in water and hence the aquatic animals get more oxygen to live. Due to which they live more in cold region.

8) Define hydrated salt.

Ans:

Hydrated salts:

The number of water molecules found in the crystalline substance is called as water of crystallization and such salts are called as hydrated salts.

For example: Blue Vitriol, Epsom salt, Gypsum, Green vitriol etc.

9) A hot saturated solution of copper sulphate forms crystals as it cools. Why?

Ans:

A hot saturated solution of copper sulphate forms crystal after cooling because when it is cooled the water molecules in it get compacted and moves close to each other and hence there is a less space for solution to remain as it is and hence it forms the crystal after cooling.

10) Classify the following substances into deliquescent, hygroscopic. Conc. Sulphuric acid, copper sulphate penta hydrate, Silica gel, Calcium chloride, and Gypsum salt.

Ans:

Deliquescent substance: Calcium chloride

Hygroscopic substance: Conc. Sulphuric acid, copper sulphate penta hydrate, Silica gel and Gypsum salt.

VI.) Long answer:

1) Write notes on

Ans:

i) Saturated solution:

The solution in which definite amount of solute is dissolved in a definite amount of solvent, at a given temperature is called saturated solution.

For example: 36 g of sodium chloride in 100 g of water at 25⁰C forms saturated solution.

And if we added further sodium chloride then it remain undissolved.

ii) Unsaturated solution:

Unsaturated solution is the solution which contains less solute than the saturated solution at a given temperature.

For example: 10 g or 20 g or 30 g of sodium chloride in 100 g of water at 25⁰C forms the unsaturated solution.

2) Write notes on various factors affecting solubility.

Ans:

There are main three factors which affects the solubility:

Nature of the solute and solvent
Temperature
Pressure

1) Nature of the solute and solvent:

The nature of solvent and solute plays main role in solubility. As water dissolves all substances, ionic and covalent but there are again some substances which cannot be dissolved by water.
The phrase “like dissolves like” express directly that dissolution occurs only if there are some similarities in between solute and solvent.
For example: common salt is the polar compound which readily dissolve in polar solvent like water.
Similarly, non-polar solutes are dissolves in non-polar solvents only.
For example: fat dissolve in ether.
But, non-polar compounds does not dissolve in polar solvent and vice versa.

2) Effect of temperature:

Generally, the solid solute dissolve in liquid solvent more when its temperature is raised.
For example: more amount of sugar will dissolve in warm water than in the cold water.
That means, in the endothermic process solubility increases as temperature is increased.
And in exothermic process, the solubility decreases as temperature is increased.
Generally, solubility of gases in liquids decreases as temperature is increased.
For example: when water is boiled it starts bubbling, because as temperature is increased the solubility of oxygen decreases due to which oxygen is escaped out through bubbling.
Also, aquatic animals live more in cold region, because at lower temperature the solubility of oxygen is more in water.

3) Effect of pressure:

When the pressure is increased the solubility of gas in liquid increases.
For example: carbonated beverages i.e. soft drinks, household cleaners congaing aqueous solution of ammonia, formalin aqueous solution of formaldehyde etc.

3.)

Ans:

a) What happens when MgSO₄.7H₂O is heated? Write the appropriate equation

MgSO₄.7H₂O is having water of crystallization 7, when MgSO₄.7H₂O is gently heated it loses 7 water molecules and forms anhydrous magnesium sulphate.

MgSO₄.7H₂O ↔ MgSO₄ + 7H₂O

Magnesium sulphate Anhydrous magnesium sulphate Heptahydrate

And if we add further few drops of water or if we allowed it to cool then the colourless anhydrous salt again get converted into hydrated salt.

b) Define solubility:

Solubility:

It is defined as the no. of grams of a solute that is dissolved in a 100 g of solvent in order to form its saturated solution at a given temperature and pressure.

For example: 30 g of sodium chloride needs 100 g of water to dissolve and to form its saturated solution at 25⁰C.

4) In what way hygroscopic substances differ from deliquescent substances.

Ans:

Hygroscopic substances:

When hygroscopic substances are exposed to the atmosphere at ordinary temperature also, they absorbs the moisture and does not dissolve.
Hence, hygroscopic substances do not change their state after exposure to atmosphere.
They may be amorphous solids or liquids.

Deliquescent substances:

When these type of substances are exposed to atmospheric air at ordinary temperature also, they absorbs the moisture and get dissolved.
Hence, Deliquescent substances changes their state on exposure with atmospheric air.
They are crystalline solids.

5) A solution is prepared by dissolving 45 g of sugar in 180 g of water. Calculate the mass percentage of solute.

Ans:

Given that, mass of sugar = 45 g

Mass of water = 180 g

Here, sugar is the solute and water is the solvent.

The mass percentage is given by,

Mass % of solute = mass of the solute/ (mass of the solute + mass of the solvent)* 100

= 45/ (45 + 180) * 100 = 45/225* 100 = 20%

Thus, the mass percentage of solute will be 20%.

6) 3.5 litres of ethanol is present in 15 litres of aqueous solution of ethanol. Calculate volume percent of ethanol solution.

Ans:

Given that, volume of ethanol = 3.5 litre

Volume of aqueous solution = 15 litre

Hence, the volume percent of ethanol solution is given by,

Volume % of the solution = volume of the solute/ volume of the solution * 100

= 3.5/15*100 = 23.33%

Thus, the volume percent of ethanol solution will be 23.33%.

VII.) HOTS

1) Vinu dissolves 50 g of sugar in 250 ml of hot water, Sarath dissolves 50 g of same sugar in 250 ml of cold water. Who will get faster dissolution of sugar? And Why?

Ans:

Here, Vinu will get faster dissolution of sugar as he dissolves 50 g of sugar in 250 ml of hot water.

Because, the solubility of solid in liquid increases as the temperature is increased.

But, Sarath dissolves 50 g of sugar in 250 ml of cold water, due to which it does not dissolve faster.

2) ‘A’ is a blue coloured crystaline salt. On heating it loses blue colour and to give ‘B’. When water is added, ‘B’ gives back to ‘A’. Identify A and B, write the equation.

Ans:

Here, A is the copper sulphate pentahydrate which is the blue coloured crystal.

When copper sulphate pentahydrate is heated it loses the blue colour and forms the anhydrous copper sulphate.

CuSO₄•5H₂O ↔ CuSO₄ + 5H₂O

Copper sulphate Anhydrous copper sulphate

Pentahydrate colourless

Blue colour

Again, if we add water to the anhydrous copper sulphate it gives again copper sulphate pentahydrate.

Thus, here A→ Copper sulphate pentahydrate CuSO₄•5H₂O

B→ Anhydrous copper sulphate CuSO₄

3) Will the cool drinks give more fizz at top of the hills or at the foot? Explain

Ans:

Because of the decrease in solubility of gases in liquid with increase in temperature, the carbonated cool drinks give more fizz at the foot hill.

If we go to higher altitudes, the temperature becomes low and the dissolved CO₂ will not escape as a fizz while at the foot it escapes as a fizz.