What is a Solution?
A solution is a homogeneous mixture of two or more two substances whose particle size ranges between 0.1nm to 1nm. Homogeneous means that the components of the mixture form a single phase.
You must have seen many types of solutions in general such as soda water, sharbat, salt solution etc. You would have seen brass utensils as well which are also the homogeneous solutions of solid into solid. We can prepare solutions of solid-liquid, solid-solid, solid-gas, liquid-solid, liquid-liquid, gas-solid, gas-liquid and gas-gas. Gasoline, alloys, air, starch solution etc. are examples of solutions.
(Image will be uploaded soon)
Components of Solution
The solution is made from two components called solute and solvent.Let’s discuss solute and solvent in detail.
Solute – The substance which is being dissolved in a solvent to form a solution is called a solute. It is present in a lesser quantity than the solvent in the solution.
Solvent – The component of a solution in which solute is being dissolved is called a solvent. It is present in more quantity than solute in solution.
For example - If we take a solution of saltwater. Then in this solution salt is solute and water is a solvent as salt is being dissolved in water and salt is present in lesser quantity than water in the solution. Thus, we can say solvent forms a major proportion of the solution.
Examples of Solutions
Sugar-water, salt solution, brass, alloys, alcohol in water, aerosol, air, aerated drinks such as Coca-Cola etc. are examples of solutions. When we work with chemistry, we generally prepare many types of solutions such as copper in water, iodine in alcohol etc.
Types of solutions
Solutions can be divided into the following types of the basis of the quantity of solute in a solution –
Unsaturated Solution – The solution in which still we can add more solute at a given temperature is called an unsaturated solution.
Saturated Solution – The solution in which we cannot dissolve more solute in the solvent at a given temperature is called a saturated solution.
Supersaturated Solution – The saturated solution in which we add more solute by raising the temperature or pressure is called a supersaturated solution. In these solutions generally, crystals start forming.
Solutions can be divided into the following types of the basis of the amount of solvent added-
Concentrated Solution – The solution in which solute is present in large quantity is called a concentrated solution.
Dilute Solution – it has a very small amount of solute in a large quantity of solvent.
Properties of a Solution
A solution possesses the following properties –
A solution is a homogeneous mixture.
The constituent particles of a solution are smaller than 10-9 metres in diameter.
Constituent particles of a solution cannot be seen by naked eyes.
Solutions do not scatter a beam of light passing through it. So, the path of the light beam is not visible in solutions.
Solute particles cannot be separated by filtration.
Solute or solvent particles do not settle down when left undisturbed.
Solutions are stable at a given temperature.
Concentration of solution
The concentration of a solution refers to the amount of solute present in a given amount of solution. The amount of solute can be represented by its mass or volume. The concentration of a solution can be represented in various ways. The relative amount of solute and solvent present in a solution can be represented by different methods of expression. These ways are as follows.
Percent Composition (by mass): The following formula is used for the calculation of percent composition.
\[\text{Percent by mass}\] = \[\left (\frac{\text{mass of solute}}{\text{mass of solution}} \right )\] x 100
Molarity: Molarity is used to express the number of moles of solute in exactly one liter of a solution. The following formula is used for the calculation of molarity.
Molarity = \[\frac{\text{Mass of solute}}{\text{volume of solution in litres}}\]
Molality: Molality is used to express the number of moles of solute dissolved in exactly one kilogram of solvent. The following formula is used for the calculation of molality.
Molality (m) = \[\frac{\text{Mass of solute}}{\text{Mass of solvent in Kg}}\]
Mole Fraction: The mole fraction (X) of a component in a solution is defined as the ratio of the number of moles of that component to the total number of moles of all components in the solution. The mole fraction of A is expressed as XA with the help of the following equation in a solution consisting of A, B, C, … we can calculate XA.
X\[_{A}\] = \[\frac{\text{moles of A}}{\text{mole of A + mole of B + momle of C +.... }}\]
Similarly, we can calculate the mole fraction of B, XB with the help of the following formula.
X\[_{B}\] = \[\frac{\text{moles of B}}{\text{mole of A + mole of B + momle of C +.... }}\]
Conclusion
We know that we use solutions in our daily life as they are an important part of our life. After going through the article we get all the necessary information related to the solution such as its properties, ways of expressing it and some common examples.
FAQs on Solution: Properties of Solution
1. What exactly is a solution in chemistry?
In chemistry, a solution is a homogeneous mixture where one substance, the solute, is uniformly dissolved in another substance, the solvent. The particles of the solute are so small (at the molecular or ionic level) that they cannot be seen with the naked eye and do not settle over time.
2. What are the main properties of a true solution?
A true solution has several key properties:
- Homogeneity: The composition and properties are uniform throughout the mixture.
- Particle Size: The solute particles are extremely small, typically less than 1 nanometer in diameter.
- Stability: The solute particles do not settle down when the solution is left undisturbed.
- Clarity: It is usually clear and transparent, and light can pass through without scattering (it does not show the Tyndall effect).
- Separation: The components cannot be separated by simple physical methods like filtration.
3. What are the different types of solutions based on the physical state of the solute and solvent?
Solutions can be formed by mixing substances in any of the three states of matter. The main types are:
- Gas in Gas: Example - Air (a mixture of nitrogen, oxygen, etc.).
- Liquid in Gas: Example - Water vapour in the air.
- Solid in Gas: Example - Sublimated iodine in the air.
- Gas in Liquid: Example - Carbonated drinks (CO2 in water).
- Liquid in Liquid: Example - Vinegar (acetic acid in water).
- Solid in Liquid: Example - Saltwater (NaCl in water).
- Gas in Solid: Example - Hydrogen gas absorbed by palladium metal.
- Liquid in Solid: Example - Dental amalgam (mercury in silver).
- Solid in Solid: Example - Alloys like brass (zinc in copper).
4. What are colligative properties and why are they important?
Colligative properties are properties of solutions that depend on the ratio of solute particles to solvent molecules, not on the chemical nature of the solute. They are important because they allow us to determine the molar mass of an unknown solute. The four main colligative properties are:
- Relative lowering of vapour pressure
- Elevation in boiling point
- Depression in freezing point
- Osmotic pressure
5. How does a true solution differ from a colloid or a suspension?
The main difference lies in the size of the dissolved particles and the resulting properties. A true solution has tiny, invisible particles and is homogeneous. A colloid has larger particles (1-1000 nm) that scatter light (the Tyndall effect) but do not settle. A suspension has the largest particles (>1000 nm), which are often visible, make the mixture cloudy, and will eventually settle down due to gravity.
6. Why do colligative properties depend only on the number of particles, not on their identity?
This is because colligative properties are essentially a result of the dilution of the solvent by the solute particles. The solute particles get in the way of the solvent molecules, affecting properties like boiling and freezing. This 'getting in the way' is a physical effect that depends on how many particles are present, not whether they are sugar molecules or salt ions. More particles cause a greater effect, regardless of their chemical makeup.
7. What is a real-world example of osmotic pressure in action?
A great example of osmotic pressure is how plants absorb water from the soil. The cell sap inside a plant's root hairs is more concentrated than the water in the soil. This difference in concentration creates osmotic pressure, which forces water to move from the soil into the roots through a semipermeable membrane, allowing the plant to stay hydrated.
8. Why is the van 't Hoff factor important for calculating properties of electrolyte solutions?
The van 't Hoff factor (i) is crucial because electrolytes, like salt (NaCl), dissociate into multiple ions when dissolved in a solvent. For example, one NaCl unit becomes two particles (Na⁺ and Cl⁻). Since colligative properties depend on the total number of solute particles, we use the van 't Hoff factor to correct for this increase in particle count to get accurate calculations for properties like freezing point depression or boiling point elevation.
