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Academic session 2026-27, Chapter 1 in the current curriculum.
Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter Solutions. This page offers a step-by-step solution to the specific question from Exercise 2, Question 3:
Define the following terms:
(i) Mole fraction (ii) Molality (iii) Molarity (iv) Mass percentage.
. With detailed answers and explanations for each chapter, students can strengthen their understanding and prepare confidently for exams. Ideal for CBSE and other board students, this resource will simplify your study experience.Define the following terms:
(i) Mole fraction (ii) Molality (iii) Molarity (iv) Mass percentage.
a) Mole Fraction - it is defined as the ratio of number of moles of one component to the total number of moles of solute & solvent present in the solution.
Mole fraction = number of moles of the component / total number of moles of all components
It is denoted by x.
Take it as binary solution, the number of the moles of solute will be nA and the number of moles of solvent will be nB, then the mole fraction of the solute in the solution is given as:

In the same manner, the mole fraction of the solvent in the solution is given as:

b) Molality- it is the number of moles of the solute dissolved per 1000g of the solvent.
It is denoted by m
Molality = mole of solute / mass of solvent in kg
Unit for molality are moles/kg
c) Molarity- it is the number of moles of the solute dissolved per litre of the solution.
It is represented by M.
Molarity = moles of solute / volume of solute in litres
Unit for molarity is moles/litre
d) Mass Percentage- the mass percentage of a component in a given solution is the mass of the component per 100g of the solution.
Mass percentage of the component = (mass of the component in the solution/total mass of the solution) x100
The reaction between A and B is first order with respect to A and zero order with respect to B. Fill in the blanks in the following table:
| Experiment |
A/ mol L - 1 |
B/ mol L - 1 |
Initial rate/mol L - 1 min - 1 |
| I | 0.1 | 0.1 |
2.0 × 10 - 2 |
| II | -- | 0.2 |
4.0 × 10 - 2 |
| III | 0.4 | 0.4 | -- |
| IV | -- | 0.2 |
2.0 × 10 - 2 |
NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:
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Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 3: Define the following terms: (i) Mole fraction (ii) Molality (iii) Molar....
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Thank you so much to help me to understand the concept. I combine this solution with my text book and arihant solution, therefore now I got the answer.