IX Practical Chemistry KBSE Experiment No. 4

To Prepare 100 ml/250 ml solution of Sodium Carbonate or Oxalic Acid of molarity 0.5 M.

Viva Voce
Q.1. What is solute?

Ans. The constituent present in smaller amount in the solution is called solute. Or Any substance which dissolves in some other substance is called a Solute.

Q.2. What is Solvent?

Ans. Any substance which can dissolve a substance to form a homogeneous mixture is called a Solvent.

OR

The component of the solution which is present in greater amount is called the solvent.


Q.3. What is Solution?

Ans. A homogeneous mixture of two or more substances is called solution.


Q.4. How many classes of solutions are there?

Ans. There are nine classes of Solution.

SOLUTE

Gas

Gas

Gas

Liquid

Liquid

Liquid

Solid

Solid

Solid

SOLVENT

Gas

Liquid

Solid

Gas

Liquid

Solid

Gas

Liquid

Solid


Q.5. Give an example of Solution of Gas in Gas?

Ans. Air.


Q.6. Give an example of Solution of Gas in Liquid?

Ans. Water Vapours in Air.


Q.7. Give an example of Solution of Solid in Gas?

Ans. Sodium in Nitrogen Gas.


Q.8. Give an example of Solution of Liquid in Gas?

Ans. Oxygen or Carbon Dioxide in water.


Q.9. Give an example of Solution of Liquid in Liquid?

Ans. Alcohal in water or Bromine in Carbon Disulphide.


Q.10. Give an example of Solid in Liquid?

Ans. Salt in water, Sugar in water, Sulphur in Carbon Disulphide.


Q.11. Give an example of Gas in Solid?

Ans. Hydrogen in Palladium.


Q.12. Give an example of Solution of Liquid in Solids?

Ans. Mercury in Sodium.


Q.13. Give an example of Solution of Liquid in Solids?

Ans. Alloys like Brass, Bronze.


Q.14. What is Isomorphous mixtures?

Ans. Solid Solutions are sometimes called Isomorphous Mixtures because the constituents can be separated on crystallization.


Q.15. What is Solubility?

Ans. The Solubility of a substance can be defined as the amount of the substance that can be dissolved by 100 grams of the solvent at a particular temperature mathematically it can be expressed as: Solubility = Weight of Solute in gm / Weight of Solvent in gm x 100


Q.16. What is Saturated Solution?

Ans. A Solution that can't dissolve any more of the solute at a mix temperature is called a Saturated Solution.


Q.17. What are the factors which effect the solubility?

Ans. (A) Pressure does not effect the solubility too much in case of a solid and liquid solutions. But the solubility is considerably effected if a gas is being dissolved in a liquid. As the pressure increases at constant temperature more and more gas dissolves.

(B) Solubility of a Gas in Liquids usually decreases with increase in temperature. Owing to this reason when we heat the water, the air bubbles come out.

(C) Solubility of solids usually increases with increase in temperature. Example KNO3 and KBr.

(D) Those solids which dissolve with the liberation of heat usually show decrease in solubility on increasing the temperature.


Q.18. What is Morality?

Ans. Molarity is the number of moles of Solute present in one litre of the solution. For

Example a molar solution is that one which contains one mole of solute dissolved per litre.


Q.19. What is Molality?

Ans. Molality is the number of moles of solute dissolved in one kg (1000gm) of solvent. Hence one molal is that solution which contains one mole of the solute in 1 kg (1000 gm) of Solvent.


Q.20. What is standard Solution?

Ans. The solution whose concentration is already known is called Standard Solution.


Q.21. What is Normal Solution?

Ans. A Normal Solution is that solution which is prepared by dissolving in gm. Equivalent of the substance and making it upto one litre (1000 C.C) of the solution.


Q.22. What is Gram Equivalent Weight?

Ans. The Gram Equivalent Weight of a substance i.e. (Equivalent Weight expressed in Gram) is

that weight which corresponds to (i.e. combines with or displaces) one gram of Hydrogen or

eight gm of Oxygen or 35.5 gm of Chlorine.


Q.23. What is Normality?

Ans. The gram equivalents of solute present in one litre of the solution is known as its

Normality.

Normality = Gm.Equivalent of Solute / Volume of Solution in Litre


Q.24. What do you understand by the strength of a Solution?

Ans. The quantity of a substance present in any known volume of the solution is called the

strength of a solution.


Q.25. How is the strength of a solution is determined?

Ans. Normality = strength per litre of a solution / Equivalent weight of a substance.


Q.26. What do you understand by "Basicity" of Acid?

Ans. The number of the replaceable or ionisabale Hydrogen atom in the molecule of an acid is

called its Basicity.


Q.27. What do you understand by "Acidity" of Base?

Ans. The number of "Hydroxyl Ions" which a molecule of base can provide is called Acidity of

Base.


Q.28. How do you determine the Equivalent weight of an Acid?

Ans. Equivlent weight of an Acid = Molecular Weight / Basicity.


Q.29. How do you determine the Equivalent weight of a base?

Ans. Equivalent weight of a Base = Molecular Weight / Acidity


Q.30. What are Monoacid Bases, Diacid Bases and Triacid Bases?

Ans. Monoacid Bases The bases which contain Hydroxyl are called Monoacid Bases e.g.

NaOH.

Diacid Bases The bases which contain two hydroxyl ion are called Diacid Bases e.g. Ca

(OH)2.

Triacid Bases The bases which contain three Hydroxyl Ions are called Triacid Bases

e.g. Al(OH)3.


Q.31. What are Monobasic Acids, Dibasic Acids and Tribasic Acids?

Ans. Monobasic Acids The acids which have only one replaceable Hydrogen atom are known

as Monobasic Acids.

Dibasic Acids The acids which have two replaceable Hydrogen atoms are known as Dibasic

Acids.

Tribasic Acids The acids which have three replaceable Hydrogen atoms are known as

Tribasic Acids.e.g. H3PO4.


Q.32. What do you understand by concentration of solution?

Ans. The amount of solute present in a given amount of solvent is called concentration of

solution.


Q.33. What do you mean by 0.1 m Solution?

Ans. It means 0.1 or 1/10 (One tenth part of molecular weight of a substance is dissolved in

one litre solution). It is also known as Deci-molar solution.


Q.34. What do you understand by "Gram Atom"?

Ans. The atomic weight of an element expressed in grams is called Gram Atom or Gram Atomic

Weight.


Q.35. What do you mean by Molecular weight?

Ans. The molecular weight of an element or a compound means the total weight of all atoms

present in the element or compound (or it is the formula weight of the element or compound).


Q.36. What is a Mole?

Ans. A mole is defined as the atomic weight or molecular weight of the substance expressed

in grams. In other words, a "Gram Atom" or a "Gram Molecule" of an element or a compound is

called a Mole.


Q.37. What is IM solution of Oxalic Acid?

Ans. If one litre solution of Oxalic Acid contains one mole or 126 gm of Oxalic Acid then

such solution is called IM solution.


Q.38. How will you calculate the molecular weight of the following. N2, Cl2, H2, H2SO4,

HNO3, NaOH and KOH.

Ans.

N2 = 2 x 14 = 28

Cl2 = 2 x 35.5 = 71

H2SO4 = 2 x 1 + 32 + 4 x 16

= 2 + 32 64 = 90

HNO3 = 1 + 14 3 x 16

= 1 + 14 + 48 = 68

NaOH = 23 + 16 1 = 40

KOH = 39 + 16 + 1 = 56


Q.39. What is the Molecular Formula of Oxalic Acid?

Ans. (COOH)2.2H2O


Q.40 What is the Molecular Weight of Oxalic Acid?

Ans. (COOH)2.2H2O

= [12 + 16 + 16 + 1] x 2 + [2 + 16]

= (45)2 + 2(18)

= 90 + 36

= 125


Q.41 How will you prepare Decimolar Solution?

Ans. A Decimolar Solution (0.1 m) of any substance can be prepared by dissolving one tenth

part (1/10) of gram molecular weight per litre of solution.


Q.42. What is 1M NaOH Solution?

Ans. IM Solution of NaOH = 1 mole i.e. 40 gm per 1000 ml. (1 litre) solution.


Q.43. What is 0.5 m solution of Oxalic Acid?

Ans. If one litre of solution of Oxalic Acid contains on mole or 126 gm of Oxalic Acid then

such solution is called 1M Solution.


Q.44. What is formula for calculating the number of mole in given weight of the

substance?

Ans. Number of Moles = Gram Weight / Molecular Weight.


Q.45. How is the concentration of a solution expressed?

Ans. The concentration of a solution can be expressed by the following

1. Molarity (m)

2. Molality (m)

3. Normality (N)


Q.46. What is meant by Hygroscopic Substance?

Ans. The substance which observes moisture from air is called Hygroscopic substance.


Q.47. What is Volume?

Ans. Space occupied by a substance is called its Volume.


Q.48. What is the unit of Volume?

Ans. The unit of Volume is litre.


Q.49. What is Litre?

Ans. The space occupied by 1 Kg of water at 4oC is called Litre.


Q.50 What is Normal Solution?

Ans. Solution obtained by dissolving are gram equivalent of a substance in one litre of

solution is called Normal Solution.


Q.51. What is one Milli-Litre?

Ans. One Milli-Litre is 1/1000 the part of a Litre.


Q.52. What is meant by N/10 Solution?

Ans. N/10 solution is a deci normal solution and is obtained by dissolving one tenth of gram

Equivalent substance is one litre of solution.


Q.53. How much Oxalic Acid is required for IM solution of 1000 ml?

Ans. 1 mole of Oxalic Acid i.e. 126 gm is required in 1000 ml solution.


Q.54. How much Oxalic Acid is required for preparing 1M solution in 250 ml?

Ans. In 1000 ml solution of 1M we require 126 gm of Oxalic Acid. In 250 ml solution of 1M we

require 250/1000 x 126 = 31.5 gm of Oxalic Acid.


Q.55. How much Oxalic Acid is required in .05 solution of 500 ml?

Ans. .05 x 126 = 5/100 x 126 = 6.3 gm.


Q.56. How much Oxalic Acid is required for preparing .05 solution of 500 ml?

Ans. 500 / 1000 x 126 x .05 = 31.5 gm of Oxalic Acid is required.


Q.57. What is relation between Mole and Gram Atom?

Ans. Mole indicates a definite number i.e. 2,4 or 6 etc. But on the other hand Gram atom

indicates a definite quantity i.e. 8.0 gm, 16 gm or 35.5 gm.


Q.58. What is the relation between Mass and Weight of the substance?

Ans. Weight = mass x acceleration due to gravity i.e. W=mg.


Q.59. Does the balance give us the mass of the substance?

Ans. The balance give us the mass of the substance.


Q.60. What kind of Lever is the Physical Balance?

Ans. It is the first kind of Lever.


Q.61. What is value of 530 mg into gm?

Ans. 530 mg = 530 gm.


Q.62. What is gram molecular weight?

Ans. The weight in gm of a molecular is called gram molecular weight.


Q.63. What is Avogadro's Number?

Ans. The number of atoms in one gram or number of molecules in one mole is called Avogadro's

Number. Its value is 6.02 x 1023.


Q.64. Define Atom?

Ans. Atom is the smallest particle of an element.


Q.65. What is a Molecule?

Ans. Smallest particle of the element or compound which can exist in free state is called a

molecule.


Q.66. What is the function of screws of the base of Physical Balance?

Ans. These screws are known as Levelling Screws as they are used to keep the balance in

horizontal position.


Q.67. How do we know that the balance is in horizontal position?

Ans. We can know it by Plumb line or Spirit Level.


Q.68. What is the function of Scale?

Ans. When beam is raised the pointer moves on the scale and if it moves equally on both

sides the balance is adjusted.


Q.69. How do we adjust the balance?

Ans. We adjust the balance with the help of two adjoining screws at the end of the beam.


Q.70 Why do we place the weight generally on the right hand side?

Ans. It is due to the reason that most of us work with the right hand and it is most

convenient.


Q.71. Should we add or remove the weight when the beam is raised?

Ans. No! The beam must be lowered, otherwise there will be jerk and the adjustment will be

disturbed.


Q.72. What is an acid?

Ans. Acids are compound whose solution in water exhibit the following properties.

1. They have a sour taste.

2. They turn blue litmus red.

3. They give Hydrogen when treated with metal.

4. They react with metal oxides and their hydroxides forming salt and water.


Q.73. What is Arhenius Definition of an Acid?

Ans. According to Arhenius "Acids are those substances which produce H ions in aqueous

solutions.


Q.74. What are Weak Acids?

Ans. Acids which ionise to small extent in water are called Weak Acids.


Q.75. What are Strong Acids?

Ans. Those acids which ionise completely are called strong Acids. e.g. HCl, H2SO4, HNO3.


Q.76. What are Hydronium Ions?

Ans. Free H+ ions do not exist freely in water and so they are associated with water and

form H3O (Hydronium Ions)


Q.77 What is Lowry and Bronsted definition of Acid?

Ans. Lowry and Bronsted defined an acid as a substance which tend to lose protons or Acids

are protons Donors.


Q.78. What is Lewis definition of an Acid?

Ans. It has been observed that donation of Hydrogen Ion in an acid is not essential since an

acid may not even possess an Hydrogen atom in its molecule. Hence Lewis an American

scientist proposed generalised concept of Acid.