Class 12 Chemistry Chapter 1 Solution Important Formula Sheet

Class 12 Chemistry starts with an interesting chapter, Solutions. This chapter covers various aspects of a solution, such as its concentration, colligative properties, effect of temperature and pressure, osmosis and reverse osmosis, vapour pressure, and other important concepts.

Chapter 1 Solutions of Class 12 Chemistry contains a lot of formulas, and frequently, numerical questions are asked from this chapter. We provide here the Class 12 Solutions formula sheet to help you get a compilation of all formulas. Students can learn and practice these formulas to solve Chapter 1 Class 12 Chemistry NCERT Solutions for better scores. 

You can also check all other important study material of the Class 12 Chemistry Solutions chapter provided by Shiksha. Read below.

Formulas for Measuring Concentration of Solution

There are several ways to check the concentration of the solution. Formulas for all quantitative methods are given below.

Mass Percentage (m/m)%:

This tool calculates the percentage of solute or solvent, or any component of the solutions, in terms of the percentage of the total solution.

$$\text{Mass \%}=\frac{m_{\text{component}}}{m_{\text{solution}}}\times 100$$

Volume Percentage(v/v)%:

Similar to mass percentage, this helps to calculate the percentage of a component in the total volume of the solution.

$$\text{Volume \%}=\frac{\text{volume of component}}{\text{total volume of solution}}\times 100$$

Parts Per Million (ppm):

PPM accounts for the total parts of the component per million components of the solution.

$$\text{ppm =}\frac{\text{number of parts of the component}}{\text{total number of parts of all components}}\times {10}^6$$

 Mole Fraction:

It is similar to the ppm calculator; the only difference it calculates part of the component as a whole, not per million.

$$\text{Mole fraction =}\frac{\text{number of moles of the component}}{\text{total number of moles of all components}}$$

Molarity (M)

It is one of the most used and asked concepts in the Class 12 examination. It calculates the number of moles of solute per liter of solvent.

$$\text{Molarity}=\frac{\text{moles of solute}}{\text{volume of solution in litres}}$$

Molality (m)

It accounts for the number of moles of solute per kg of the solvent.

$$\text{Molality}=\frac{\text{moles of solute}}{\text{mass of solvent in kg}}$$

Solubility and Henry's Law

Every solute doesn't dissolve in every solvent, there is a specific limit set by nature. Henry's law provides a way to calculate the solubility numerically.

Henry's Law

$$p=K_H{x}_{\mathrm{gas}}$$ p = Partial pressure of the gas

K_H = Henry’s law constant 

x =  Mole Fraction

NCERT-Based Table - Henry's Law Constant for a Few Gases

Vapour Pressure of Liquid Solutions

When a solution is given heat in a closed vessel, both the components evaporate and come to an equilibrium between the vapour phase and the liquid phase. Quantitative methods are given by Rauolt's Law. 

Dalton’s law of partial pressures

P_total = P₁ + P₂ + P_3......

Raoult’s Law (for volatile components)

$$p_i=x_i{p}_i^0$$ $p_i^0$= vapour pressure of pure component $i$
Total vapour pressure in a binary solution:

$$p_{\mathrm{t}\mathrm{o}\mathrm{t}\mathrm{a}\mathrm{l}}=p_1+p_2=x_1{p}_1^0+x_2{p}_2^0$$

Ideal and Non-ideal Solutions

on the basis of the rauolt's law, the solutions are classified in two special cases:

For ideal solutions:

$$\Delta_{\rm mix} H = 0,\quad \Delta_{\rm mix} V = 0$$For Non-Ideal Solutions:

$${\mathrm{For\; Endothermic:\; \Delta }}_{\mathrm{m}\mathrm{i}\mathrm{x}}\mathrm{H\; >}<br>0,{\mathrm{\Delta }}_{\mathrm{m}\mathrm{i}\mathrm{x}}V>0$$

$${\mathrm{For\; Exothermic:\; \Delta }}_{\mathrm{m}\mathrm{i}\mathrm{x}}\mathrm{H\; <}<br>0,{\mathrm{\Delta }}_{\mathrm{m}\mathrm{i}\mathrm{x}}V<0$$

Relative lowering of vapour pressure

$$\frac{\mathrm{\Delta }p}{p^0}=x_2$$Also, $$\mathrm{\Delta }p=p^0-p=p^0(1-x_1)$$

Approximate formula for dilute solutions

$$\frac{p^0 - p}{p^0} = \frac{n_2}{n_1}$$ $$\frac{p^0-p}{p^0}=\frac{w_2\mathrm{/}{M}_2}{w_1\mathrm{/}{M}_1}$$

Colligative Properties and Molar Mass

Solutions exhibit several properties based on the number of particles of solute in the solution. We'll discuss formulas for change in colligative properties.

Boiling point elevation:

$$\Delta T_b=K_{b}m$$ Freezing point depression:

$$\Delta T_f=K_{f}m$$ In simple terms change in boiling or freezing point (ΔT ) is directly proportional to molality (m). Kb and Kf are constants that depend on the solvent.

Formula of K_b and K_f constants

$\mathrm{K\_f}=\frac{R\times M_1\times {T_f}^2}{1000\times {∆}_{\text{fus}}H}$

$\mathrm{K\_b}=\frac{R\times M_1\times {\mathrm{T\_b}}^2}{1000\times {∆}_{\text{vap}}H}$

Osmotic Pressure and Molar Mass

Osmotic Pressure for Dilute Solutions

$${\Pi }_{}=C\times R\times T$$ Molar mass from osmosis

van ’t Hoff factor (i): Electrolytes and Association

$$i=\frac{\text{observed colligative property}}{\text{calculated colligative property (assuming no dissociation)}}$$ Colligative equations with van't hoff factor :

$$\Delta T_b=i\times K_{b}m$$ $$\Delta T_f=i\times K_{f}m$$ $$\Pi =i\times \frac{n_2\times R\times T}{V}$$