NCERT Solutions | Class 12 Chemistry Chapter 2 | Solutions

CBSE Solutions | Chemistry Class 12
Check the below NCERT Solutions for Class 12 Chemistry Chapter 2 Solutions Pdf free download. NCERT Solutions Class 12 Chemistry were prepared based on the latest exam pattern. We have Provided Solutions Class 12 Chemistry NCERT Solutions to help students understand the concept very well.
NCERT | Class 12 Chemistry
Book: | National Council of Educational Research and Training (NCERT) |
---|---|
Board: | Central Board of Secondary Education (CBSE) |
Class: | 12th |
Subject: | Chemistry |
Chapter: | 2 |
Chapters Name: | Solutions |
Medium: | English |
Solutions | Class 12 Chemistry | NCERT Books Solutions
NCERT Exercises
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 1.
Solution.
Mass of solution = Mass of benzene + Mass of carbon tetrachloride = 22 g +122 g = 144 gMass percentage of benzene =

∴ Mass percentage of CCl4
= 100 – Mass percentage of benzene = 100 – 15.28 = 84.72%
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 2.
Solution.
Let mass of solution = 100 g∴ Mass of benzene in the solution = 30 g
∴ Mass of carbon tetrachloride = 100 – 30g = 70g
Molar mass of benzene (C6H6) = 78 g mol-1
Molar mass of CCl4 = 12 + 4 × 35.5 = 154 g mol-1
∴ No. of moles of benzene

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 3.
(a) 30 g of Co(NO3)2.6H2O in 4.3 L of solution
(b) 30 mL of 0.5 M H2SO4 diluted to 500 mL (atomic mass of cobalt = 58.7)
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 4.
Solution.
Moles of urea = 0.25 moleMass of solvent (water) = 1 kg = 1000 g
Molar mass of urea (NH2CONH2) = 14 + 2 + 12 + 16 + 14 + 2 = 60 g mol-1
∴ Mass of urea in 1000 g of water = 0.25 mol × 60 g mol-1 = 15 g
Total mass of solution = 1000 + 15 g = 1015 g = 1.015 kg
Thus, 1.015 kg of solution contain urea = 15 g
∴ 2.5 kg of solution will require urea
= \(\frac { 15g }{ 1.015kg } \) × 2.5 K.g = 37 g
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 5.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 6.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 7.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 8.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 9.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 10.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 11.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 12.
Solution.

NCERT Exercises
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 1.
Solution.
A solution is a homogeneous mixture of two or more pure substances which are chemically non-reacting, whose composition can be varied within certain limits. The component which is present in a large proportion in the solution is called solvent and the component present in relatively small proportion is called solute.Types of solutions : Depending upon the physical state of solvent, solutions can be divided into three main groups :
(a) Gaseous solutions :
- Solvent – gas, solute – gas. c.g., air (oxygen and nitrogen).
- Solvent – gas, solute – liquid, c.g., humidity in air.
- Solvent – gas, solute – solid, c.g., camphor in nitrogen.
(b) Liquid solutions:
- Solvent – liquid, solute – gas. c.g., aerated drinks.
- Solvent – liquid, solute – liquid, c.g., ethanol in water.
- Solvent – liquid, solute – solid, c.g., salt solution in water.
(c) Solid solutions:
- Solvent – solid, solute – gas. c.g., H2 in palladium.
- Solvent – solid, solute – liquid, c.g., amalgam of Hg with Na.
- Solvent – solid, solute – solid, c.g., alloys.
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 2.
Solution.
Solution of hydrogen in palladium and dissolved gases in minerals.NCERT Solutions for Class 12 Chemistry Chapter 2, Question 3.
- Mole fraction
- Molality
- Molarity
- Mass percentage.
Solution.
(i) Mole fraction : Mole fraction of a constituent (solute as well as solvent) is the ratio of the number of moles of one component to the total number of moles of all the components present in the solution. If nA and nB are the number of moles of solvent and solute respectively then
(ii) Molality : Molality of a solution is defined as the number of moles of the solute dissolved in one kilogram of the solvent. It is denoted by m. It is expressed as
(iii) Molarity : Molarity of a solution is defined as the number of moles of the solute dissolved in one litre or one dm3 of the solution. It is denoted by M and is expressed as
(iv) Mass percentage : It may be defined as mass of solute in grams per 100 g of solution. \(\frac { w }{ W } \) or mass Percentage
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 4.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 5.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 6.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 7.
Solution.
300 g of 25% solution contains solute = 75 g400 g of 40% solution contains solute = 160 g
Total solute = 160 + 75 = 235 g
Total solution = 300 + 400 = 700 g
% of solute in the final solution = \(\frac { 235 }{ 700 } \) × 100 = 33.5%
% of water in the final solution = 100 – 33.5 = 66.5 %
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 8.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 9.
- Express this in percent by mass.
- Determine the molality of chloroform in the water sample.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 10.
Solution.
There is a strong hydrogen bonding in water as well as in alcohol molecules. When alcohol and water are mixed the intermolecular hydrogen bonding between the alcohol and water molecules in the mixture is weak. Due to weaker interactions, the solution shows positive deviations from ideal behaviour. As a result, the solution will have higher vapour pressure and lower boiling point than alcohol and water separately.NCERT Solutions for Class 12 Chemistry Chapter 2, Question 11.
Solution.
As the temperature is increased, the equilibrium in a gas in liquid solution shifts in backward direction since dissolution of gas in liquid is an exothermic process. Hence the solubility of the gases decreases.NCERT Solutions for Class 12 Chemistry Chapter 2, Question 12.
Solution.
Henry’s law : The solubility of a gas in a liquid at a particular temperature is directly proportional to the pressure of the gas in equilibrium with the liquid at that temperature.or
The partial pressure of a gas in vapour phase is proportional to the mole fraction of the gas (x) in the solution. p = KHX
where KH is Henry’s law constant.
Applications of Henry’s law :
(i) To increase the solubility of CO2 in soft drinks, soda, etc., the bottles are sealed under high pressure.
(ii) In deep sea diving, increased pressure increases the solubility of atmospheric gases in blood. Oxygen is used up in the metabolism but N2remains dissolved and forms bubbles in the blood, when diver comes to the surface. To reduce this danger, N2 is replaced by He which is much less soluble in biological fluids.
(iii) In the functions of lungs – when air enters the lungs, partial pressure of oxygen is high. This oxygen combines with haemoglobin to form oxyhaemoglobin. Partial pressure of O2 in tissues is low, hence O2 is released from oxyhaemoglobin which is used for the functions of the cells.
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 13.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 14.
Solution.

Examples :
- Benzene + toluene
- n – Hexane + n – heptane
- Chlorobenzene + bromobenzene
- Ethyl bromide + ethyl iodide
II. Non-ideal solution : A solution which does not obey Raoult’s law of vapour pressure is called non-ideal solution. They are of two types.
(a) Non-ideal solution with negative deviation : When intermolecular forces between A and B are stronger than between A-A and B-B, then intermolecular force increases, volume decreases, vapour pressure decreases and heat is released.
Examples:
- Chloroform + acetone
- Water + sulphuric acid
- HCl + water
- Acetone + aniline
(b) Non-ideal solution with positive deviation: When intermolecular forces between A and B are weaker than that of A-A and B-B.
In this case intermo lecular force decreases, volume increases, vapour pressure increases, enthalpy increases.
∆V = +ve, ∆H = + ve, ∆P = + ve
So, it is called non-ideal solution with positive deviation.
PA > xA P°A, PB > xB P°B and PS > xA P°A + xB P°B
Examples :
- Ethanol + water
- Chloroform + ethanol
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 15.
Solution.
Vapour pressure of pure water at the boiling point (P°) = 1 atm = 1.013 barVapour pressure of solution (Ps) = 1.004 bar
Let mass of solution = 100 g, then, mass of solute = (W2) = 2 g
Mass of solvent (W1) = 100 – 2 = 98 g
Applying Raoult’s law for dilute solution,

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 16.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 17.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 18.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 19.
- molar mass of the solute
- vapour pressure of water at 298 K.
Solution.



NCERT Solutions for Class 12 Chemistry Chapter 2, Question 20.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 21.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 22.
Solution.
π = CRT∴ In the first case, 4.98 = \(\frac { 36 }{ 180 } \) × R × 300 = 60R ….(i)
In the second case, 1.52 = C × R × 300 …. (ii)
Dividing (ii) by (i) we get, C = 0.061 M
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 23.
- n – Hexane and n-octane
- l2 and CCl4
- NaClO4 and water
- Methanol and acetone
- Acetonitrile (CH3CN) and acetone (C3H6O).
Solution.
- n-Hexane and n-octane : London dispersion forces as both the molecules are non-polar.
- I2 and CCl4 : London dispersion forces as both the molecules are non-polar.
- NaClO4 and water: Ion-dipole interactions as NaClO4 in water gives Na+ and ClO–4 ions. These ions interact with polar water molecules.
- Methanol and acetone : Dipole-dipole interactions as both the molecules are polar.
- Acetonitrile and acetone : Dipole-dipole interactions as both the molecules are polar.
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 24.
Cyclohexane, KCI, CH3OH, CH3CN.
Solution.
- Cyclohexane and M-octane both are non-polar. Hence, they mix completely in all proportions.
- KCl is an ionic compound while n-octane is non-polar. Hence, KCl will not dissolve at all in n-octane.
- CH3OH and CH3CN both are polar but CH3CN is less polar than CH3OH. As the solvent is non-polar, CH3CN will dissolve more than CH3OH in n-octane.
Thus, the order of solubility will be KCl < CH3OH < CH3CN < Cyclohexane.
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 25.
- Phenol,
- Toluene,
- Formic acid,
- Ethyleneglycol,
- Chloroform,
- Pentanol.
Solution.
- Partially soluble because phenol has polar -OH group and non-polar C6H5 group.
- Insoluble because toluene is non-polar while water is polar.
- Highly soluble because formic acid can form hydrogen bonds with water.
- Highly soluble because ethylene glycol can form hydrogen bonds with water.
- Insoluble because chloroform is an organic liquid.
- Partially soluble because -OH group is polar but the large hydrocarbon part (C5H11) is non-polar.
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 26.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 27.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 28.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 29.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 30.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 31.
Solution.
The depression in freezing point is in the order :Acetic acid (CH3 – COOH) < trichloroacetic acid (Cl3C – COOH)
< trifluoroacetic acid (F3C – COOH)
Fluorine, being most electronegative, has the highest electron withdrawing inductive effect. Consequently, trifluoroacetic acid is the strongest acid while acetic acid is the weakest acid. Hence, trifluoroacetic acid ionizes to the largest extent while acetic acid ionizes to the minimum extent to give ions in their solutions in water. Greater the ions produced, greater is the depression in freezing point. Hence, the depression in freezing point is the maximum for the fluoroacetic acid and minimum for acetic acid.
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 32.
(Ka = 1.4 × 10-3, Kf = 1.86 K kg mol-1)
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 33.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 34.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 35.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 36.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 37.

Plot this data also on the same graph paper. Indicate whether it has positive deviation or negative deviation from the ideal solution.
Solution.

As the plot for Ptotal dips downwards, hence the solution shows negative deviation from the ideal behaviour.
NCERT Solutions for Class 12 Chemistry Chapter 2, Question 38.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 39.
Solution.


NCERT Solutions for Class 12 Chemistry Chapter 2, Question 40.
Solution.

NCERT Solutions for Class 12 Chemistry Chapter 2, Question 41.
Solution.

NCERT Class 12 Chemistry
Class 12 Chemistry Chapters | Chemistry Class 12 Chapter 2
Chapterwise NCERT Solutions for Class 12 Chemistry
-
NCERT Solutions For Class 12 Chemistry Chapter 1 The Solid State
NCERT Solutions For Class 12 Chemistry Chapter 2 Solutions
NCERT Solutions For Class 12 Chemistry Chapter 3 Electro chemistry
NCERT Solutions For Class 12 Chemistry Chapter 4 Chemical Kinetics
NCERT Solutions For Class 12 Chemistry Chapter 5 Surface Chemistry
NCERT Solutions For Class 12 Chemistry Chapter 6 General Principles and Processes of Isolation of Elements
NCERT Solutions For Class 12 Chemistry Chapter 7 The p Block Elements
NCERT Solutions For Class 12 Chemistry Chapter 8 The d and f Block Elements
NCERT Solutions For Class 12 Chemistry Chapter 9 Coordination Compounds
NCERT Solutions For Class 12 Chemistry Chapter 10 Haloalkanes and Haloarenes
NCERT Solutions For Class 12 Chemistry Chapter 11 Alcohols Phenols and Ethers
NCERT Solutions For Class 12 Chemistry Chapter 12 Aldehydes Ketones and Carboxylic Acids
NCERT Solutions For Class 12 Chemistry Chapter 13 Amines
NCERT Solutions For Class 12 Chemistry Chapter 14 Biomolecules
NCERT Solutions For Class 12 Chemistry Chapter 15 Polymers
NCERT Solutions For Class 12 Chemistry Chapter 16 Chemistry in Everyday Life
NCERT Solutions for Class 12 All Subjects | NCERT Solutions for Class 10 All Subjects |
NCERT Solutions for Class 11 All Subjects | NCERT Solutions for Class 9 All Subjects |
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