Chapter 2 chemistry.pptx ; PPT PPT

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1. chemistry Class 9 Chapter: 2 Matter

2. Everything that has mass and volume is called matter. Matter: 1- Fundamental states Solid Liquid Gas 2- Exotic states Plasma (high temperature) EBC (low temperature) Liquid Crystal (combined state)

3. EBC : Einstein-Bose Condensate State of matter. That occurs when a set of atoms is cooled almost to absolute zero then atoms demonstrate collective behaviour and act like single super atom. Intermolecular force of attraction for EBC is so strong molecules cannot move.

4. Liquid Crystal: It is the intermediate state between solids and liquids. The substances which have arrangements like solids but freedom of motion like liquids are called liquid crystal.

5. Plasma State: It was discovered by adding energy to gas. As a result some electrons left their atoms and formed positive and negative ions by ionization. The ionize gaseous state of matter is called plasma.

6. Properties of matter in bulk  are called macroscopic properties. While microscopic properties are the properties of matter, properties of atoms and molecules. examples of Macroscopic properties:- Density, Volume, Viscosity, Resistance , surface tension of liquid .

7. Solid state Atoms and molecules are tightly packed in fixed positions. They can vibrate. They cannot move. They have fixed volume and a rigid shape because of its close arrangements. Examples: aluminium and diamond are solids at room temperature. Solids are non-compressible and cannot diffuse into each other due to this reason. High density because their particles are closely packed. They lack fluidity and do not flow or conform to the shape of their container. Fluidity: the ability to flow.

8. Liquid state Liquid consists of molecules that are closely packed similar to solids. The molecules of liquids are fairly free to move. Mobility: the ability to move. They have fixed volume but not fixed shape, taking the shape of their container. Examples: ice water, alcohol, and gasoline are liquid at room temperature. The densities of liquids are much greater than those of gases but are similar to those of solids. The spaces among the molecules of liquids are negligible, similar to solids. Liquids are fluid, meaning they can flow and spread within their container.

9. Gaseous state Atoms or molecules are widely space and move freely. Highly compressible by applying pressure. This occur because there are large empty spaces between their molecules. Example: When you compress air in a balloon. Gases adopt the shape and volume of their containers. Helium, nitrogen and carbon dioxide are examples of gases at room temperature. The density of gases is low compared to solids and liquids because their particles are much more spread out. Fluidity of gases is very high, and they can spread out to fill entire volume of their container.

10. Gases can also diffuse and effuse, which is negligible in solids but operates in liquids as well. Effusion- It is the movement of gas molecules from one container to another through tiny holes.

11. The Compressibility of gases: Gases can be compressed squeezed into a smaller volume because there is so much empty space between atoms or molecules in the gaseous state.

12. Macroscopic Properties that can be visualized by naked eye and we can take measurements easily. Some common examples of macroscopic properties of matter include density, fluidity, compressibility.

13. Exotic states of matter Exotic states of matter are the physical states that are less common than fundamental states of matter. These states exist under extreme conditions, such as ultra-cold temperatures or high energies. They are not widely understood. These states of matter can be classified into three categories: i . High-temperature states ii. Low-temperature states iii. Combined states

14. High Temperature States The exotic state of matter that requires extreme heat to form is known as high-temperature state. Such states include plasma, quark gluon plasma, hot dense matter, degenerate matter, and strange matter. Here we will only discus plasma. Plasma is the fourth state of matter. Naturally, plasma is present in the Sun and other stars and produces through lightning. It is produced through certain high-intensity lamps on Earth (as explained in fig 2.5 that are used in streetlights, gymnasiums, warehouses, large retail facilities, stadiums, and plant growing rooms, etc .

15. Electrons in the gaseous atoms become excited, and then fall back to lower energy levels, emitting light of a different colour in the process.

16. In plasma, atoms gain a significant amount of energy, leading to the loss of their electrons. This creates a mixture of positively charged ions and hot free electrons and some neutral atoms .

17. How plasma is formed Once a gas is heated to an extremely high temperature, the electrons within its atoms begin to oscillate, potentially leading to their release from the atom itself. As a result, certain atoms may acquire a positive charge. This process gives rise to a unique state of matter known as plasma, which comprises of positively charged ions, neutral atoms, and unbound electrons .

18. Properties Plasma Particles Charged particles (ions, electrons) Dominant forces Long-range, electromagnetic Shape & volume Indefinite shape & volume Conductivity Excellent conductor Magnetic field interaction Strong Kinetic energy High Comparison of plasma with fundamental states of matter -

19. Think of it this way Using the table 2.1, compare the properties of plasma with fundamental states of matter.

20. ii. Low-Temperature States The exotic states of matter that form under extremely cold conditions are called low-temperature states . Such states include Bose-Einstein Condensate (BEC), Fermionic Condensate, and Quantum. Bose-Einstein Condensate (BEC) is fifth and unique state of matter .

21. Picture this: imagine a group of dancers on a dance floor, moving independently like particles in a gas as shown in figure 2.6 (a). Now, imagine these dancers slowing down and moving together, forming a single, coordinated group as shown in figure 2.6 (b).

22. In a BEC state, particles, when cooled to almost absolute zero ( - 273.15 degrees Celsius or -459.67 degrees Fahrenheit), merge into a unified state, acting like a giant "super-particle ” . Temperature Scales

23. All atoms have the same energy and momentum, perfectly synchronized. It is worth noting that BECs are not found naturally; they are created in labs under specific conditions.

24. Properties of Bose-Einstein Condensate (BEC)-

25. Is Bose-Einstein Condensate a superfluid? Yes, a Bose-Einstein Condensate can be superfluid because it allows atoms to flow without any resistance. This happens because the atoms in the condensate occupy the same quantum state, behaving like a single entity. Viscosity is a measure of a fluid´s resistance to flow. Water have lower viscosity and Honey have higher viscosity. Deform – change in shape. Coherence – to stick together.

26. Think of it this way Using the table 2.2, compare the properties of Bose-Einstein Condensate (BEC) with fundamental states of matter.

27. iii. Combine State (Intermediate States) Have you ever heard of a state of matter that shares properties with solid, liquid, and gas? It is called a combined state. A few examples of these states include amorphous solids, plastic crystals, and liquid crystals. In higher classes, you will delve deeper into these examples, but for now, let us focus on the liquid crystals . It is an excellent example of a combined state or intermediate state. Liquid crystals are a state of matter that exist in a state between solid and liquid.

28. They have a unique arrangement of particles [figure 2.7 (a,b)]. The molecules in a liquid crystal are typically rod-shaped and can flow like a liquid while maintaining some degree of alignment.

29. Liquid crystals are highly responsive to changes in temperature and electrical signals, which makes it possible to adjust their molecular alignment and alter their color . These characteristics make liquid crystals useful in a wide range of technological applications, particularly in electronic device displays, where their ability to control color through temperature or electrical inputs is essential. Liquid crystals are like special materials that can change their color and stuff when we heat them up or send electrical signals through them. This makes them perfect for things like screens that need to show different colors and images. That's why liquid crystals are used in technologies like LCD screens, where precise control of light and color is essential. LCD-Liquid Crystal Display.

30. Properties of liquid crystal-

31. Think of it this way Using the table 2.3, Compare the properties of Liquid crystals with fundamental states of matter.

32. A few common examples of these applications include Liquid Crystal Displays (LCDs), Oscillographic and TV displays that also use liquid crystal screens as shown in figure 2.8 (a, b, c).

33. Oscillograhic- instruments used for measuring and recording changes in electrical signals over time.

34. Allotropes The property of an element to exist in different physical forms is called allotropy. Atoms of the same element arranged in different manners in the same physical state in allotropes. They are different structural forms of the same element. Example: Diamond, graphite and buckyballs are three important allotropes of carbon.

35. Allotropic forms of Carbon- Solids are generally known for their fixed shape, high density, and resistance to compression, which result from the close packing of particles held together by strong, attractive forces . However, it's essential to recognize that not all solids have the same particle arrangement. An excellent example is carbon, which can exist in a diamond, graphite, Buckminsterfullerene etc. Each of these forms of carbon has distinct properties attributed to its unique arrangement of particles .

36. Test yourself What are the three common states of matter that we encounter in our everyday lives? What is plasma, and in which natural phenomena can it be observed? Discuss the conditions required for the formation of a Bose Einstein Condensate, and what unique properties does it exhibit at such extreme temperatures? How liquid crystals exhibit properties of both liquids and solids?

37. Diamond- It is composed of carbon atoms arranged in a tetrahedral configuration, where each carbon atom forms four strong covalent bonds with others. This type of bonding results in a rigid, three dimensional structure that accounts for the diamond's remarkable hardness . Due to this strong bonding, diamonds are unable to conduct electricity. This is because all of the outer shell electrons of the carbon atoms are involved in bonding, leaving no free electrons for electrical conductivity. Diamond has very high melting and boiling point. Due to this strong covalent bonding, it requires very high energy to separate the atoms that's why diamond has high melting and boiling point.

38. Why diamond is a good conductor of heat but not electricity? So diamond is a bad conductor of electricity. diamond is a good conductor of heat because of  strong covalent bonding and low photon scattering .

39. Graphite T he composition of graphite is distinct from that of a diamond. Graphite has a layered arrangement of carbon atoms bonded to three other carbon atoms through covalent bonds . This creates a giant molecule-like structure that results in a slippery and conductive composition. There is a weak bond present between the layers of graphite, allowing them to easily sl ide over one another. Graphite is composed of flat two dimensional layers of hexagonally arranged carbon atoms. In a layer, each C-atom is covalently bonded to three other carbon atoms. Weak intermolecular bonds exist between each layers to slide over one another without breaking the bonds.

40. An unbonded electron on each carbon atom within each layer allows delocalized electrons to move freely between the layers, as shown in figure 2.11. This is what enables graphite to conduct electricity .

41. Back in 1985, Rice University's Richard Smalley and Robert Curl employed a laser beam to vaporize a graphite sample, transforming it from a 3D matrix into a 2D one. The 2D matrix is then naturally shaped into a round configuration of carbon atoms known as buckminsterfullerene, or “buckyballs”. Figure 2.12 illustrates the structure of buck minster fullerene . Buckyballs(C-60), also known as fullerenes, have a football like fused hollow ring structure made up of twenty hexagons and twelve pentagons. Each of its 60 carbon atoms are bonded to 3 carbon atoms.

42. Test your self What are allotropic forms of solids, and why do they have distinct properties? 2. Provide examples of allotropic forms of carbon, and briefly describe their structural differences. 3. How does the atomic arrangement in diamond differ from that in graphite, and how do these differences affect their properties? 4. Can you compare and contrast the electrical conductivity of diamond, graphite, and fullerenes based on their atomic structures?

43. Types of Matter Based on Their Chemical Composition - Substance : A piece of matter in pure form is termed as a substance. Every substance has a fixed composition and specific properties. Every substance has a physical and chemical properties. To make our study easy, we classify substances into two broad categories i.e. pure substance and impure substance . Matter around us has different characteristics, such as the air we breathe (a gas), the fuel we burn in our cars (a liquid), and the road we drive on (is a solid).

44. Pure substance: A pure substance, is matter that has unique properties and a composition that remains the same from sample to sample. Examples of pure substances include water, oxygen and table salt (sodium chloride). All pure substances are either elements or compounds. Impure substance: I mpure substances are  made up of two or more pure substances mixed together in any proportion . They may be homogeneous or heterogeneous i.e. their composition is not uniform throughout the bulk. They are all mixtures. Examples: air, seawater, petroleum, and a solution of sugar in water are all impure substances.

45. All pure substances are either elements or compounds. Elements: Element are substances that cannot be broken down into simpler substances. On the molecular level, each element is made up of only one type of atom, as shown in figure 2.13 (a). Compounds: Compound are substances composed of two or more elements; they contain two or more kinds of atoms, as shown in figure 2.13 (b), water is a compound made up of two elements, namely hydrogen and oxygen.

46. When hydrogen gas burns in oxygen gas, the elements hydrogen and oxygen come together in a fixed ratio of 2:1 and create the compound water. Likewise, water can be separated into its constituent elements by passing an electrical current through it, which is a chemical reaction.

47. Electrolysis is  a chemical reaction that occurs when an electric current is passed through a substance .

48. Why is the amount of hydrogen twice the amount of oxygen? T he volume of hydrogen generated is twice the volume of oxygen gas, because  the number of hydrogen molecules is twice that of oxygen molecules .

49. Mixtures: Figure 2.13 (d) illustrates a mixture of substances. Mixtures are combinations of two or more substances in which each substance retains its chemical identity. Mixture are of two types . i.e. H eterogeneous M ixtures and H omogeneous M ixtures . Examples: Mixture of sand and water, Mixture of sugar and water.

50. Homogeneous Mixture: Sugar mixed with water is the most common example of a homogeneous mixture.  Homogeneous mixtures   can be defined as the mixtures which possess the same properties and combination throughout their mass. Heterogeneous Mixture: A mixture of sand mixed with water is an example of a heterogeneous mixture. Heterogeneous mixtures possess different properties and compositions in various parts i.e. the properties are not uniform throughout the mixture.

51. Types of Mixture: Mixtures bases on the texture, mixture are of two types: Homogeneous mixtures . Heterogeneous mixtures . Homogeneous mixtures: Homogeneous mixtures exhibit a uniform composition and properties throughout. These mixtures are also known as solutions. Examples of homogeneous mixtures include saltwater, air, and brass. Brass is a metal alloy of copper and zinc containing trace amount of lead iron and other elements. The uniformity of these mixtures is due to the molecular level mixing of their components.

52. Homogeneous mixtures can be more challenging to separate into their original components, often requiring processes such as distillation, crystallization, or chromatography. These processes will be discussed in more detail in Chapter 17, called Chemical Analysis. The distinctive properties of homogenous mixtures are given below: • Invisibility of particles: The solute particles are so small that they cannot be seen, even with a microscope and solute particles can pass easily through a filter paper. • Stability: The particles do not settle out or separate on standing.

53. Examples of homogeneous mixtures include true solutions such as saltwater, gaseous mixtures such as air, and alloys such as brass. The uniformity of these mixtures is due to the molecular level, mixing of their components. Homogeneous mixtures can be more challenging to separate into their original components, often requiring processes such as distillation, crystallization, or chromatography. These processes will be discussed in detail in Chapter 17.

54. Distillation is a separation technique used to separate liquid (the solvent) from a mixture and keep the liquid part. Crystallization is a technique used for the  purification of substances.  A separation technique to separate solids from a solution. Chromatography is a scientific method for separating the components found in a mixture .

55. True solutions: In these mixtures, the solute (the substance being dissolved) is completely dissolved in the solvent (the substance in which the solute is dissolved), resulting in a single-phase system . An example is a copper sulphate solution, where copper sulphate (solute) is uniformly dissolved in water (solvent).

56. Solution: A solution is a mixture of two or more substances in which one substance is dissolved in the water. Homogeneous means that no particles or parts of different substance can be seen. When one substance dissolved the solution looks exactly the same. A substance that is dissolved is called a solute and a substance in which it is dissolved is called a solvent. In solution, the particles are microscopic, less than 1nm in diameter. A solution is a very stable mixture and the solute does not separate from the solvent itself.

57. In salt solution, salt is the solute and water is solvent. More than one solute may be present in a solution. Examples: In soft drinks, water is a solvent while other substances like sugar, salts and carbon dioxide. In air where Nitrogen gas is solvent and oxygen, carbon dioxide and trace are solute.

58. On the basis of physical states of solvent and solute can be categorized as solid, liquid and gaseous solutions. Generally, solutions are found in three physical states depending upon the physical state of the solvent, Examples: Air is gaseous, sea water is liquid solution and alloy solid solution in real life. T he meaning of the term 'alloy' is  a substance that formed from the combination of two or more metals .  Gaseous Solution: In gaseous solutions solvent is a gas and solute can be a gas or liquid or solid. Examples: A mixture of nitrogen and hydrogen used in Haber´s process (ammonia formation) and other is mixture of ammonia and carbon dioxide used for urea preparation.

59. Fog, clouds, and mist are examples of solutions where liquid water (solute) is dissolved in air (solvent). Smoke is a solution of carbon particle in gaseous air in our daily life. Liquid Solutions: Carbonated drinks are solutions where solvent is liquid water and solute is gaseous carbon dioxide. Rectified spirit produced by fermentation of sugarcane, Vinegar (acetic acid in water), are examples of solutions where liquid dissolved in liquid, Brine and sugar syrup are solutions of solid salt and sugar in water. Rectified spirit contains 95% ethanol with 5% water. A rectified spirit is highly concentrated ethanol which has been purified by means of repeated distillation, a process that is called rectification. fermentation,  chemical process by which molecules such as glucose are broken down anaerobically . Brine is  a high-concentration solution of salt (usually sodium chloride) in water .

60. Solid Solutions: Hydrogen gas on the nickel metal surface is used in ghee industry where hydrogen gas is solute and nickel catalyst is solvent. Solution of any metal (solid) in liquid mercury is called amalgam. Alloy industry is very common these days. Alloys are formed by mixing different metal (Brass, Bronze, Steel). Brass is a metal alloy of copper and zinc containing trace amounts of lead, iron, and other elements. Bronze is an alloy made of two elements — copper and tin. Steel is a kind of metal alloy that's made of iron and carbon .

61. Aqueous Solutions: Aqueous solution is formed by dissolving a substance in water. The dissolved substances in an aqueous solution may be solids, gases, or other liquids. In order to be a true solution, a mixture must be stable. Example: sugar in water and table salt in water. Water is called universal solvent because it dissolves majority of compounds present in earth´s crust. Aqueous solutions are mostly used in the laboratories.

62. Saturated Solution: A solution containing maximum amount of solute at a given temperature is called saturated solution. When a small amount of solute at given temperature is added in solvent, solute dissolves very easily in the solvent. If the addition of solute is kept on, a stage is reached when solvent cannot dissolves any more solute. At this stage, further added solute remains undissolved and it settles down at the bottom of the container. On the particle level, a saturated solution is the one, in which undissolved solute is in equilibrium with dissolved solute. At this stage, dynamic equilibrium is established. Although dissolution and crystallization continue at given temperature, but the net amount of dissolved solute remains constant.

63. Unsaturated Solution: A solution which contains lesser amount of solute than that which is required to saturate it at a given temperature, is called unsaturated solution. Such solutions have the capacity to dissolve more solute to become a saturated solution. Supersaturated Solution: When saturated solutions are heated, they develop further capacity to dissolve more solute. Such solutions contain greater amount of solute than is required to form a saturated solution and they become more concentrated. The solution that is more concentrated than a saturated solution is known as supersaturated solution.

64. Supersaturated solutions are not stable. Therefore, an easy way to get a supersaturated solution is to prepare a saturated solution at high temperature. It is then cooled to a temperature where excess solute crystallizes out leaves behind a saturated solution.

65. The solutions are classified as dilute and concentrated on the basis of relative amount of solute present in them. Dilute Solution: Dilute solutions are those which contain relatively small amount of dissolved solute in the solution. Concentrated Solution: Concentrated solutions are those which contain relatively large amount of dissolved solute in the solution. Example: Brine is a concentrated solution of common salt in water. T hese terms describe the concentration of the solution. A ddition of more solvent will dilute the solution and its concentration decrease.

66. Solubility Solubility is the maximum amount of solute which dissolves in a specified amount of solvent at a specific temperature. T he solubility of substance depends on the solvent used, as well as temperature and pressure. Generally, solubility increases with an increase in temperature, but this is not always the case. When a substance is added to a solvent to form a solution, the effect of temperature on solubility can vary. There are three possibilities:

67. Heat is absorbed: When substances like KNO 3 , NaNO 3 , and KCl are added to water, the test tube becomes cold , indicating that heat is absorbed during the dissolution process. This type of dissolving process is called 'endothermic’ . For such solutes, solubility usually increases with an increase in temperature. This is because heat is required to break the attractive forces between the ions of the solute. The surrounding molecules fulfil this requirement, causing their temperature to fall, and the test tube to become cold. Solvent + Solute + Heat Solution.

68. Why is sodium nitrate more soluble than potassium nitrate? Sodium nitrate is more soluble in water than potassium nitrate because sodium ions have a smaller size and higher charge density compared to potassium ions, which helps sodium nitrate molecules dissociate more easily in water. This results in more sodium nitrate ions being able to interact with water molecules and increase its solubility. Homework Why potassium nitrate is more soluble than potassium chloride?

69. Why potassium nitrate is more soluble than potassium chloride? Electrostatic Force between potassium cation and chloride ion is way stronger than that with nitrate ion. So, more energy is needed to break the bond between potassium chloride than potassium nitrate.

70. 2. Heat is given out: On the other hand, when substance like Lithium sulphate (Li 2 SO 4 ) and C erium(III) sulphate (Ce 2 (SO 4 ) 3 ) are dissolved in water, the test tube becomes warm, indicating that heat is released during the dissolution process. This type of dissolving process is called ‘e xo thermic’ . In such cases, the solubility of the salts decreases with an increase in temperature. This is because attractive forces among the solute particles are weaker than solute solvent interactions, resulting in the release of energy. Solvent + Solute Solution + Heat.

71. W hy does solubility of cerium sulfate decrease with temperature? The solubility of cerium sulfate decreases with temperature because it is an exothermic process. Why it is exothermic process? The dissolution of cerium sulfate is exothermic because, even though the attractive forces between solute particles (cerium and sulfate ions) are relatively weak, the energy released when these ions interact with water molecules (hydration energy) is greater than the energy required to separate the ions from the solid. This results in a net release of energy, making the process exothermic.

72. 3. No change in heat: In some cases, during the dissolution process, neither heat is absorbed nor released. When salt like NaCl is added to water, the solution temperature remains almost the same. In such cases, temperature has the minimum effect on solubility.

73. KEY POINTS: The solubility of solutes depends on temperature. Depending on the nature of solute there is either: Increase in solubility with temperature. Example: KCl, NH 4 Cl etc. b) Decrease in solubility with temperatures. Example: Na 2 SO 4 , Ca(OH) 2 etc.

74. An example of a solute whose decreases in solubility with increasing temperature is calcium hydroxide, which can be used to treat chemical burns and as an antacid. Antacid: An antacid is a chemical compound, which neutralizes excessive hydrochloric acid released in the stomach. Antacids are some bases, which react with the acid (hydrochloric acid) to release salt and water.

75. ii. Heterogeneous mixtures Heterogeneous mixtures are mixtures containing non-uniformly distributed components. These mixtures consist of distinct phases, where each phase has different properties. Examples of heterogeneous mixtures include wet sand and milk, oil and water mixtures, and salads. As shown in figure 2.15, 2.16. The components of these mixtures can often be separated by simple physical means such as filtration. For example, soil particles can be separated from water by filtration. When the mixture is passed through a filter, many of the particles are removed. Repeated filtrations will give water with a higher state of purity.

76. Dispersed particles: particles refer to tiny particles that are scattered or spread out throughout a medium, such as a liquid or gas. Examples: dust particles, spread out and mixed with water or air. Dispersion medium: is the substance or material in which dispersed particles are scattered or spread out. Example: Water is dispersion medium for sugar solution, Air is dispersion medium for dust particles.

77. Types of Heterogeneous mixtures- Colloids- These are heterogeneous mixtures in which the solute particles are larger than those present in the true solutions but not large enough to be seen by naked eye. A colloid is a mixture that has particles ranging between 1 and 1000 nanometres in diameter, yet are still able to remain evenly distributed throughout the solution. These are also known as colloidal dispersions because the substances remain dispersed ( distribute ) and do not settle to the bottom of the container. The particles in such system dissolve and do not settle down for a long time.

78. But particles of colloids are big enough to scatter the beam of light. It is called Tyndall effect. We can see the path of scattered light beam inside the colloidal solution. Tyndall effect is the main characteristic which distinguishes colloids from solutions. Hence, these solutions are called false solutions or colloidal solutions. Examples are starch, albumin, soap solutions, blood, milk, ink jelly and toothpaste, etc. Albumin: is the main protein made by the liver found in blood plasma.

79. Purifying heterogeneous mixture by Filtration.

80. Types of colloids are a mixture of solids, liquids, or gas, and each combination has specific name. The figure below and the table provide examples of these different combinations. Take a look at the figure to get a better understanding of the various types.

81. You often have seen on medicine bottles the word 'suspension' or 'mix well before use'. What does that mean? These words indicates that content in the bottle has some particles can be settled at bottom. Therefore, mixing them ensure their uniform distribution making the medicine effective. These suspensions are another type of heterogeneous mixtures in which particles are undissolved, and can be settled down at bottom if undisturbed.

82. 2. Suspension- A suspension is defined as the heterogeneous mixture in which the solid particles are spread throughout the liquid without dissolving in it. It is mixture of undissolved particles in a given medium. Particles are big enough ( greater than 1000nm ) to be seen with naked eyes. Examples are chalk in water ( milky suspension ), paints and milk of magnesia ( suspension of magnesium oxide in water ).

83. Tyndall Effect- Tyndall effect is the main characteristic which distinguishes colloids from solutions. Hence, these solutions are also called false solutions or colloidal solutions and can be translucent in nature. Colloids are translucent because they scatter light blurring objects behind This is due to particle size, which causes the Tyndall effect a distinguishing feature between colloids and true solutions. Translucent: allow some light to pass through.