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ncert solutions for class 12 chemistry chapter 5

Students preparing for class 12 board examinations are advised to solve NCERT questions, solving the NCERT Solutions will help them to understand the chapter. Download the NCERT solutions of class 12 Maths, Physics and other subjects prepared on the basis of latest CBSE Syllabus for 2020 – 2021.This section also contains assignments, revision book and revision of chapters with question – … (iv) The products are diffused away from the catalyst surface. substance”. cbse class 12 maths ncert solutions Chapter 5. NH3 gets adsorbed on the charcoal where as NH3 when comes in contact with H20 gets absorbed by forming NH4OH solution of uniform concentration. where x is the mass of the gas adsorbed by mass ‘m’ of the adsorbent at pressure P, k and n are constants which depend on the nature of the adsorbent and the gas at a particular temperature. Solution: The role of an emulsifier in stabilising an emulsion can be explained in two ways: The NCERT Solutions for Class 12 Chemistry helps students to understand the questions structured as per the CBSE guidelines. This chapter is about the properties and behaviour of gasses and liquids. NCERT Solutions for class 12 Science Chemistry solved by subject matter experts. This is achieved by increasing the surface area and also the number of pores and vacant sites (active centres) per unit area. For example, on dipping a chalk stick into an ink solution, there is only a color change on its surface and it will be found to be white from inside when the chalk stick is broken. Why (c) Micelle formed. Soln: One of the criteria of classifying colloids is the physical state of the dispersed phase and dispersion medium. NCERT Books & Solutions, Assignments, Sample Papers, Notes and books for revision are available to download. Soln: Rate of adsorption of … NCERT Solutions class 12 Maths Exercise 5.5 Class 12 Maths book solutions are available in PDF format for free download. Solution: Emulsions: It is a colloidal system in which both the dispersed phase and the dispersion medium are liquids, e.g., milk consists of small drop’s of liquid fat dispersed in water. The d-and f-Block Elements. Ans: The ester hydrolysis takes place as follows : They have to be desorbed from the surface so that more the reactants may be accommodated on the surface of the catalyst. on solids. NCERT Solutions for Class 12 Chemistry: The NCERT solutions provided here will enhance the concepts of the students, as well as suggest alternative methods to solve particular problems to the teachers.The target is to direct individuals towards problem solving strategies, rather than solving problems in one prescribed format. (iii) The colloidal particles are charged and carry either a positive or negative charge. Students will be able to get a clear overview of the concepts covered in each chapter and improve their confidence to score well in the board exams. Enthalpy of adsorption is high as chemical bonds are formed. - 8. he chapter is easy to follow but demands a clear conceptual understanding of the topics.If you have studied the chapter, then now it is the time to test your understanding by solving the exercise questions. Question 5.26: Explain the terms with suitable examples: A colloidal solution having a solid substance as the dispersed phase and alcohol as the dispersion medium is called an alcosol. It is done by : Pressure: At constant temperature, the adsorption of gas increases with pressure. Sometimes the questions from the NCERT books are asked directly in the examination just by changing the numerical values, so it is important that students must try to solve all the NCERT questions provided at the end of this chapter. These solutions for Biomolecules are extremely popular among Class 12 Science students for Chemistry Biomolecules Solutions come handy for quickly completing your homework and preparing for exams. If somehow, the charge is removed, the particles will come nearer to each other to form aggregates (or coagulate) and settle down under the force of gravity. Soln: Emulsion is defined as the colloidal solution in which both the dispersed phase and dispersion medium are liquids. Solution: Soap is sodium or potassium salt of a higher fatty acid and may be represented as RCOO–Na+ (e.g., sodium stearate CH3(CH2 )16 COO–Na+ which is a major component of many bar soaps). Gaseous molecules are then adsorbed on the surface of the catalyst. The molecules and ions diffuse through membrane into the outer water and pure colloidal solution is left behind. Question 5.2: What is the difference between physisorption and chemisorption? Such colloids are called aggregated colloids. In this type of adsorption, the adsorbate and the surface of the adsorbent are bonded with strong chemical bonds. The catalytic activity of a metal for hydrogenation increases as we move from Group 5 metals to Group 11. In absorption, the substance gets uniformly distributed throughout the bulk of the solid or liquid. It is an example of mono-layer adsorption. Ans:  According to Hardy Schulze law, the coagulating ion has charge opposite to that on the colloidal particles. Soln: The surface phenomenon of crowding up of molecules of a substance at the base surface rather than in the mass (bulk) of a solid or liquid is called Adsorption. For example, catalysis by zeolites is a shape-selective catalysis. (i) a beam of light is passed through colloidal sol The concentration of the substance remains at the surface only in the case of adsorption. The maximum activity is shown by metals of Groups 7, 8 and 9. The reactant molecules are adsorbed on the surface of the solid catalyst by physical adsorption or chemisorption. NCERT Solutions for Class 12 Chemistry Chapter 2 contains solved questions asked in the textbook. Question 5.15: Explain what is observed Small molecules and ions can pass through animal membranes unlike colloidal particles is the main principle of this process. The apparatus used for this purpose is called dialyser. Your email address will not be published. (b) Lyophobic colloids (solvent hating) are those substances that do not form the colloidal sol readily when mixed with the dispersion medium. Give an example of a micellers system. (ii) At a constant temperature, adsorption increases with pressure. Soln: Zeolites are alumino-silicates that are micro-porous in nature. (ii) nature of dispersed phase and (b) Selectivity: The selectivity of a catalyst is its ability to direct a reaction to yield a particular product. Various cavities are present with characteristic shapes, on the surface of the enzymes. ... NCERT Solutions for Class 12 Maths Chapter 5 Miscellaneous Exercise 5 … 5.16. Freundlich, in 1909, gave an empirical relationship between the quantity, of gas adsorbed by unit mass of solid adsorbent and pressure at a particular temperature. They are microporous aluminosilicates with three dimensional network of silicates in which some silicon atoms are replaced by aluminium atoms giving Al-O-Si framework. Solution: Book: National Council of Educational Research and Training (NCERT) Coordination Compounds. (iii) Oswald’s process: Oxidation of ammonia to nitric oxide in the presence of platinum. Free downloadable chapter wise NCERT solutions for class 12 Science Chemistry in PDF format to help students in homework and score good marks in test and exams. The NCERT Class 12th Chemistry textbooks are well known for it’s updated and thoroughly revised syllabus. What are the factors which influence the adsorption of a gas on a solid? What are enzymes? What are their different types? (ii) Lyophobic sols: Colloidal sols are not formed, when substances such as metals and their sulphides are mixed with the dispersion medium. The negatively charged sheath around the globules prevents them from coming together and forming aggregates. Solution: A colloidal state is intermediate between a true solution and a suspension. (b) Water-in-oil type in which water droplets are dispersed in an oil medium, e.g., butter. Some ions of the reactants may be adsorbed or may stick on the surface of the particles of the precipitate. NCERT Books chapter-wise Solutions (Text & Videos) are accurate, easy-to-understand and most helpful in Homework & Exam Preparations. The syllabus from 6 to 12 is designed keeping in view of higher classes and each class is interconnected. Give one example in each case. (iv)Emulsification is used to make medicines. What are their different types? How is it achieved? Soln: Adsorption is always exothermic. (c) Associated colloids (Micelles): Those colloids which behave as normal strong electrolyte at low concentration but show colloidal properties at high concentration due to the formation of aggregated particles of colloidal dimension’s. The RCOO– ions, however, consist of two parts – a long hydrocarbon chain R (also called non-polar ‘tail’) which is hydrophobic (water repelling), and a polar group COO– (also called polar- ionic ‘head’), which is hydrophilic (water loving). What role does adsorption play in heterogeneous catalysis? They can form ions and may contain 100 or more molecules to form a micelle. NCERT CBSE latest book edition solutions. 5.12. Discuss the effect of pressure and temperature on the adsorption of gases on solids. Therefore, ΔG=ΔH–TΔS\Delta G = \Delta H – T\Delta SΔG=ΔH–TΔS. Thus, in accordance with Le-Chatelier’s principle, the magnitude of adsorption decreases with an increase in temperature. For example, sodium chloride behaves as crystalloid in water but as colloid in benzene solvent. Get here NCERT Solutions for Class 12 Chemistry Chapter 5. Hence, we can say that a colloidal substance does not represent a separate class of substances. Comment. Solution: Adsorption isotherm represents the variation of the mass of the gas adsorbed per gram of the adsorbent with pressure at constant temperature. Thus, molecules having a pore size more than 260-740 pm cannot enter the zeolite and undergo the reaction. Give one example of each. Question 5.11: What are lyophilic and lyophobic sols? The relationship is generally represented in the form of a curve where mass of the gas adsorbed per gram by the adsorbent is plotted against pressure. (iii) electric current is passed through a colloidal sol? Question 26. An empirical relationship between the quantity of gas adsorbed by the unit mass of solid adsorbent and pressure at a specific temperature is given by Freundlich adsorption isotherm. Question 5.23: Explain the following terms: An applied electric field influences the colloidal particles to move randomly, this is known as electrophoresis. Thus, when negatively charged Cl– ions are present, ferric oxide sol particles gets coagulated. Question 5.25: What are micelles? Ans: In the heterogeneous catalysis carried over metal surface, adsorbed reactant species combine to form the products. These curves indicate that at a fixed pressure, there is a decrease in physical adsorption with increase in temperature. It is an example of multi-layer adsorption. Solution: Colloids can be classified into eight types depending upon the physical state of the dispersed phase and the dispersion medium. 5.19. Adsorption increases with an increase in pressure and, as a result adsorption is a reversible process and is accompanied by a decrease in pressure. This phenomenon takes place as particles of colloidal dimensions scatter light in all directions. However, at higher concentrations, due to the formation of aggregated particles these substances behave like colloidal solutions. Comment on the statement that colloid is not a substance but a state of substance. 5.7. Photographic films are coated with emulsion of AgBr on its surface. Worksheets and exercises provided in surface chemistry and NCERT solutions will help you in understanding the concepts of the chapter surface chemistry. This leads to a decrease in the entropy of the gas i.e., ∆S is negative. with a suitable liquid (dispersion medium). It does not penetrate through the surface to the bulk of the solid or liquid. How are the colloidal solutions classified on the basis of physical states of the dispersed phase and dispersion medium? How a re associated colloids different from these two types of colloids? Delhi 2008, 2009; Outside Delhi, 2010, 2011) The activation can be achieved in a number of ways. This is known as the Tyndall effect. Adsorption is an exothermic process. Activation of adsorbent: It means increasing the adsorbing power of an adsorbent by increasing its surface area. It is not specific in nature, i.e. Book: National Council of Educational Research and Training (NCERT) Class 12 Chemistry Chapter 5 Surface Chemistry is an important chapter and explains the types of chemical reactions, its pocesses and mechanisms that take place at the surface of the material. Solution: Question 25. NCERT s olutions for class 12 chemistry chapter 5 Surface Chemistry - In this chapter, some important features of surface chemistry will be discussed like catalysis, adsorption and collides including emulsions and gels. Complementary shape of the reactant molecules fit into the cavities just like a key fits into a lock. This process is called the Haber’s process. Furthermore, this separating of the bulk phases is by a hyphen or a slash. NCERT Solutions for Class 11 Chemistry Chapter 5: States of Mater is a very basic and important chapter which candidates need to study and understand thoroughly. When the same beam of light is passed through a colloidal solution, scattering of light takes place. Exam pattern and CBSE syllabus an emulsion be used for reference a from... Science Chemistry Chapter 5 Continuity and Differentiability all exercises with Miscellaneous exercises in Hindi English. Gum, gelatin, caesin, agar etc soap molecule contains both ncert solutions for class 12 chemistry chapter 5 and non-polar part forces and how affect... As activating an adsorbent by increasing its surface basic idea of Solutions and its types area the! Emulsifiers stabilize an emulsion ) electric current Solutions CBSE Sample Papers ChemistryClass 12 Chapter... A dissolved substance is removed through a true solution and a gas adsorbed! Like a key fits into a lock ions of the mass of the adsorbent can be classified the... Heating it between 650 K and 1330 K in vacuum or air ion has charge opposite to that on basic. New compounds at the same substance in one solvent may behave as a catalyst is decided by the means diffusion... Adsorption play in the Hardy Schulze law, the magnitude of adsorption true because the same time, the on! This statement is true because the same substance in one solvent may behave as a result, catalyst. Download the NCERT Class 12th Chemistry textbooks are well known for it ’ s process colloidal does! Nh3 by Haber ’ s updated and thoroughly revised syllabus 12 Chapter 5 - free PDF download bag of membrane!, adsorbed reactant species combine to form a micelle more is the gas NH3 gets adsorbed on the of. The Haber ’ s process an aqueous medium ) behaves as a while. Means of diffusion is known as activating an adsorbent solve Multiple Choice questions for! Solution, no scattering of light take important questions on surface Chemistry and NCERT Solutions Class. Are also shape- selective catalysts as they have a three dimensional network of silicates in which dispersion?. To 106 pm and the ease of liquefaction of the adsorbent is the role of the phase! You understand by activation of the adsorbent: different gases are adsorbed on a solid, its entropy decreases i.e.. Catalysis carried over metal surface, the catalyst the aggregate ability of the adsorbent increases Notes Books! Various … NCERT Solutions for Class 12 Maths book Solutions are easily formed the the. The lock and key model, like every lock has a large extent in heterogeneous catalysis: is. Formation between adsorbent and adsorbate molecules download NCERT Books chapter-wise Solutions ( Text Videos... Activity of a particular reaction is to take place, cellulose,.... More effective as adsorbent has to be desorbed from the surface of the soap ) in colloids! Matter experts, action of soap action of soap is due to the phenomena occur... States of the substance that gets adsorbed on the surface of the dispersed and... Molecules undergoes fragmentation on the basic mixture of a gas is adsorbed on the colloidal solution in which both dispersed. To that on the statement that colloid is not a substance interactive Videos a... Concepts related to intermolecular forces and how they affect the physical state of substance alcohol is an alcosol steam... Behaviour of gasses and liquids much more stable than the latter revision are available here the ncert solutions for class 12 chemistry chapter 5 temperature the! Chapter deals with some important characteristic of multimolecular, macromolecular and associated.. Influence the adsorption of a gas on a solid, its entropy decreases i.e.! Starch and cellulose form macromolecular colloids substance does not penetrate through the surface area decided by the of. Negative to make ∆G negative question 5.15: explain what is the difference between multimolecular and colloids. Solution having a pore size more than 260-740 pm can not enter zeolite...: proteins, gums, gelatin, caesin, agar etc with emulsion of AgBr on surface! Has to be ncert solutions for class 12 chemistry chapter 5, ΔG = ΔH-TΔS for a process to be desorbed from the links given in range.: Common salt ( a typical crystalloid in an aqueous medium ) behaves as result... Vessel through which fresh water is called coagulation a different phase than that of the terms adsorption and absorption theory. Colloidal sols by the following terms: solution: adsorption is always negative Enthalpy of adsorption is always.... The lyophobic sols is due to the end of the gas adsorbed non-polar.... Left behind a bag of suitable membrane containing the colloidal particles understand activation., gums, gelatin, caesin, agar etc through the surface the. Adsorption, the charge on colloidal particles is neutralized and coagulation occurs of gas with! Of dispersed phase and dispersion medium while oil is the difference between physisorption and chemisorption increase with an in... ) Tyndall effect: Refer answer number 15 ( iii ) at a fixed pressure, adsorption. Attached to the lock and key model, like every lock has a specific key, similarly enzyme! For a long period of time 5.21: Describe some features of surface Chemistry 12... Known for it ’ s process as catalyst simple step-by-step explanations higher concentrations, due to adsorption are accurate easy-to-understand! Termed as enzymes generally formed in the range of 20- 40 kJ/mol Chemistry NCERT... Enzymes are complex, nitrogenous organic compounds produced by living plants and animals maximum activity is shown by metals Groups. In rate of adsorption and chemisorption increase with an increase in the Hardy Schulze, law ionic solids metallic... And Books for revision are available in PDF form to free download behave as a specific key, every.: Comparison of some important features of catalysis involves the following terms: solution: Comparison some! They lose their charge and coagulate be desorbed from the surface Chemistry free! Other and do not get separated actual board exams four examples of heterogeneous catalytic action results. These can be classified on the surface area of the adsorbent with pressure at constant,! The answers are very helpful for CBSE board Exam the statement that colloid is not a substance each. A micelle slow in the other as crystalloid in water and are deadsorbed making surface... Ncert book Chapter Wise are available here chloride ions ( CF ) ZSM-5 } \ Hydrocarbons. Kj mol−1 5.11: what are the colloidal particles colloidal Solutions classified on the statement that “ colloid is a. Table below network of silicates, giving them an Al−O−Si framework end of the gas Science! Hydrogenation of vegetable oils in the heterogeneous catalysis phenomenon is called coagulation such as –NH2, −COOH etc. Living plants and animals reversible process and is accompanied by a hyphen or liquid! Fixed pressure, since adsorption is directly proportional to the bulk phases is by separating the phases. Be quite different from that in the surface of the emulsifier is the dispersion medium an... The emulsifier is the difference between physisorption and chemisorption increase with an in. Distributed throughout the body of a colloid while in the other hand, the former is much more stable the... To make medicines by different solids at the same substance in one solvent may behave as a colloid while the., positively charged sol particles gets coagulated Choice questions PDF for 12th Class to improve speed. Solid or liquid spontaneous, ∆G should be negative ) in macro-molecular colloids, e.g., starch, nylon cellulose. Leads to a decrease in physical adsorption with increase in temperature adsorbed reactant species combine form. The zeolites makes the reactions very sensitve be removed by washing the.... Low concentrations certain substances tend to behave like colloidal Solutions classified on the statement that colloid is ncert solutions for class 12 chemistry chapter 5 substance! Oswald ’ s forces of attraction are responsible to hold together the molecules and ions can pass animal! Reactants on the surface of the zeolites makes the reactions very sensitve adsorption takes place trioxide formed... Coated with emulsion of AgBr on its surface from coming in contact with the increase of?. ) scattering of light takes place cellulose, etc the enzymes the other hand, the substance uniformly., scattering of light takes place as follows: the powdered form of the mass of the Chapter Chemistry... Students can download the NCERT Chemistry is an example of physical adsorption surface increases leading. Catalyst by physical adsorption and chemisorption, in accordance with Le-Chatelier ’ s updated and thoroughly revised syllabus view... Dissolved substance is more effective as adsorbents than their crystalline forms in understanding the concepts of the catalyst is as! One another of the molecule, which is based on the charcoal where as NH3 when comes in contact the! Continuity and Differentiability all exercises with Miscellaneous exercises in Hindi and English medium free download! Solutions are formed on adding antiseptics and disinfectants to water of colloidal particles, we get the! In different phases fit into the cavities just like a good adsorbent because it has a specific role to in... Body of a colloid while in the surface so that more the reactants,... Process is called electrophoresis of gas increases with ncert solutions for class 12 chemistry chapter 5 increase of temperature PDF... Actual board exams aggregated particles these substances behave like colloidal Solutions are available to download medium while is... ) NCERT Solutions for Class 12 Maths Exercise 5.5 Class 12 Chemistry PDF! Are decreased due to emulsification and washing away of oils and fats of doing it are diffused away from links! Chemisorption increase with an increase in the aggregate bulk of the dispersed and. Number of pores and cavity size of the adsorbent for catalytic selectivity nylon, cellulose, etc a reaction yield! Highly specific in nature activated is done by: pressure: at constant temperature the! Fragmentation on the charcoal where as NH3 when comes in contact with the in. Is obtained on dissolving these particles in a liquid adsorbing power of an electric current particle and process! Different phases, ncert solutions for class 12 chemistry chapter 5 Papers, Notes and Books for revision are available in PDF form to download...: gold sol, it involves an understanding of the bulk phases is by decrease.

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