NCERT Solutions Class 12 Chemistry Chapter – 2

NCERT Solutions Class 12 Chemistry Chapter 2 – Solutions

In everyday life, we rarely come across pure substances. The majority of them are a mix of two or more substances, and their composition determines their significance in life. For instance, the air we breathe is mostly composed of oxygen and nitrogen, and the water we drink has a trace amount of different salts dissolved in it. Our blood is also made up of a variety of components. Furthermore, gold, brass, bronze and stainless steel and other alloys are some of the best examples of mixes. Hence, the NCERT solutions class 12 Chemistry chapter 2 – Solutions, focuses on liquid solutions and their properties.

NCERT Solutions for Chemistry covers many different chapters making it a complicated subject for many students. It has solutions for all the chapters of class 12, which aims at enhancing the concept for students, in addition to suggesting a different approach to the topic covered in chapter 2 – solution. It helps students clarify their doubts on various topics and solve problems using a logical method. Chemistry class 12  chapter 2 NCERT Solutions helps students understand the chapter, study the question paper patterns and prepare for board exams. 

The NCERT solutions class 12 Chemistry chapter 2 deals with types of solutions and their properties. Other major topics covered in this chapter are Raoult’s law and Henry’s law, the concentration of solutions, the vapour pressure of liquid solutions, abnormal molar masses, and colligative properties.

Key Topics Covered In NCERT Solutions Class 12 Chemistry Chapter 2

The key topics covered in NCERT solutions class 12 Chemistry chapter 2 – Solutions include

Students can click on the above topics to refer to the study material, revision notes, and important questions that can help them during their examination. In addition, a brief of each topic is given below.

The key topics covered in NCERT solutions class 12 Chemistry chapter 2 in brief:

Exercise 2.1: Introduction to Solutions

Solution is a homogeneous mixture of two or more substances in the same or different physical phases. The substances forming the solution are called components of the solution. Based on the number of components, a solution of two components is called a binary solution.

Students may refer to NCERT solutions class 12 Chemistry chapter 2 solutions chapter for detailed information.

Exercise 2.2: Solute and Solvent

In a binary solution, the solvent is the component present in large quantities, while the other component is known as solute. For example, salt solution. The NCERT solutions class 12 Chemistry chapter 2 exercise 2.2 explains in detail solvent and solute. Students can refer to the study material in addition to important questions by clicking on the link provided above. 

Exercise 2.3: Classification of solutions

Types of solutions are seen based on the physical state of solute and solvent. NCERT solutions class 12 Chemistry chapter 2 classification of a solution is as under.

If water is used as a solvent, the solution is called an aqueous solution, and if not, the solution is called a non-aqueous solution. Students can click here for more information on class 12 Chemistry chapter 2 exercise 2.3 provided by Extramarks. Extramarks gives a detailed explanation of all the topics in NCERT solutions class 12 Chemistry chapter 2.

Exercise 2.4: Strength of Solutions

The strength of solution refers to the amount of solute dissolved per unit of solution or solvent. There are several methods for determining the strength of a solution which are as follows.

1. Mass Percentage (%w/w): “It denotes the mass of a component in 100 g of solution.

Mass % of a component = Mass of the component in the solution  X 100

                                             The total mass of solutions 

2. Volume Percentage (%v/v): “It represents the volume of a component in a solution of 100 mL.

Volume % of a component = Volume  of component X 100

                                                 Total volume of solution

3. Mass by Volume Percentage (% w / v): “It denotes the mass of the solute in grams in 100 mL of solutions.”

Mass by volume % = Mass of solute in g  X 100

                                  The volume of solution in mL

Students may click here to access the NCERT solutions class 12 Chemistry chapter 2.

4. Parts Per Million (ppm):

Parts per million = No. of parts of the component  X 106

                                Total no. of all the components of sol.

Mass to mass, volume to volume, and mass to the volume are all ways to express concentration in parts per million. For more information, students may refer to NCERT solutions class 12 Chemistry chapter 2.

5. Mole Fraction (x): “It denotes the number of moles of a solute in one mole of solution.”

Mole fraction = No. of moles of the component

                           Total no. of moles all the component

If the amount of moles A and B in the binary mixture is nA and  nB, respectively, the mole fiction of A will be 

      xA =nA

_____________

    nA + nB

6. Molarity, M: It represents the number of moles of solute in 1 litre of solution.

Molarity, M = Moles of solute 

                          Vol. of sol in L

Molarity is measured in milligrams per litre and is denoted by the letters ‘M ‘ or ‘Molar.’ “The density of a solution is its mass per unit volume.”

Density = Mass of solution

                  Vol. of solution

Students may refer to class 12 Chemistry solutions chapter 2 Exercise 2.4  provided by Extramarks for detailed notes on Molarity. In addition, Extramarks offers study notes, important questions, and sample question papers specific to NCERT solutions class 12 Chemistry chapter 2.

7. Molality, m: It denotes the number of moles of solute present per kilogramme of solvent

 Molality, m = Moles of solute

                       Mass of solvent in kg

Molality is measured in mol/kg, which can also be written as ‘m’ or ‘molal.’

8. Normality, N: It denotes the number of solute equivalents in 1 litre of solution.

Normality, N = No. of Equivalents of solute

                              Vol. of sol. in L

No. of equivalents, eq =     Weight_____  

                                       Equivalent weight(W/E)

E = M, where Z is the valency factor.

      Z

Extramarks provides detailed study material as well as revision notes for NCERT solutions class 12 Chemistry chapter 2. Students may click here to access notes on Exercise 2.4

Exercise 2.5: Some Important Relationships

Some of the important relationships defined in class 12 Chemistry chapter 2 NCERT solutions are as under.

Dilution Law: When we dilute a solution with solvent, the amount of solute remains constant, and we can write:

M1 V1 =M2V2 &  N1 V1=N2 V2

Molarity and Normality: Normality =Z X Molarity

Important Note: The temperature does not affect the mass percent, ppm, mole fraction, or molality; however, temperature influences molarity and normality. This is because the volume is affected by temperature, whereas mass is not.

Solubility: The maximum amount of solute that can be dissolved in a given amount of solvent given temperature is known as its solubility at that temperature.

The solubility of a solute in a liquid depends upon factors shown in below

• Nature of solute
• Nature of the solvent
• The temperature of the solution
• Pressure(Gases)

For a detailed explanation of solubility, students may refer to NCERT solutions class 12 Chemistry chapter 2 by clicking here.

Exercise 2.6: Henry’s Law

This law establishes a quantitative relation between pressure and solubility of a gas in a solvent. It applies only to gas-liquid solutions. As per Henry’s law, at a constant temperature, the solubility of a gas in a liquid is directly proportional to the mole fraction of the gas(x) in the solution.

The formula is p=KH  x 

where KH  = Henry law constant

The value of Henry law constantly differs for different gases at the same temperature. The value of KH increases with the increase in temperature; therefore solubility of gases increases with decreasing temperature. Due to this reason, cold water is more sustainable for aquatic life than warm water.

Henry’s law applies to

• The manufacturing of aerated drinks
• During deep water diving
• Mountain climbers and those who live in high altitudes will benefit from this.

NCERT solutions class 12 Chemistry chapter 2 has detailed information on Henry’s law that students can access for free on Extramarks.

Exercise 2.7: Raoult’s Law

This law established a quantitative relation between the partial vapour pressure and the mole fraction of the solution. Raoult’s law follows only liquid-liquid solutions. This law state is only for the solution of volatile liquids; the partial vapour pressure(p) of each component is directly proportional to its mole fractions(x).

So

px

Or p=p0x

where p0 is the vapour pressure component at the same temperature.

Exercise 2.8: Colligative properties

Colligative is a Latin word that means ‘together binds’. Colligative properties depend upon the number of solute particles in a solution, irrespective of their nature. More details of colligative properties are shown in NCERT  class 12 chapter 2 solution.

NCERT solutions class 12 Chemistry chapter 2 are available on Extramarks website.Each solution has been explained in detail by the experts of Extramarks. In addition to chapter 2, students can access NCERT Solution for all other Chemistry chapters of class 12. Furthermore, students can click on the links provided below to access the study material of other classes.

• NCERT Solution Class 11
• NCERT Solution Class 10
• NCERT Solution Class 9
• NCERT Solution Class 8
• NCERT Solution Class 7
• NCERT Solution Class 6
• NCERT Solution Class 5
• NCERT Solution Class 4
• NCERT Solution Class 3
• NCERT Solution Class 2
• NCERT Solution Class 1

NCERT Solutions Class 12 Chemistry Chapter 2 Exercise & Answer Solutions

The  NCERT Chemistry class 12 chapter 2 offers several exercises and answer solutions that are vital for students studying for an examination. The best way to study and practice these exercises mentioned in Chemistry class 12 starts is by going through the chapter entirely. Then it would help if students practised the numerical and reactions properly. Students must also be well-versed with the diagrams and formulas. The Extramarks answer solutions include diagrams and formulae wherever needed, that are aptly labeled. Students may refer to the solutions to help them better understand the concept and build a strong foundation for higher studies. 

For Extramarks exercise questions, students may click on NCERT solutions class 12 Chemistry chapter 2 exercise questions.