10th Chemistry Chapter 13,14,15,16 Notes.

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Q1: How Plants Synthesize Carbohydrates? 

Ans: Carbohydrates are synthesized by plants through photosynthesis process from CO₂ and H2O in the presence of sunlight and green pigment chlorophyll. 

6CO2 + 6H2O C6H12O6 

Q2: Give the Characteristics of Monosaccharides? 

Ans: Characteristics of Monosaccharides: 

(i) Monosaccharides are white crystalline solids. 

(ii) They are soluble in water. 

(iii) They have sweet taste. 

(iv) They cannot be hydrolyze

(i) Polysaccharides are amorphous solids 

(ii) They are insoluble in water 

(iii) They are tasteless 

(iv) They are non-reducing compound

(i) They regulate the amount of sugar level in our body. 

(ii) Dietary fiber helps to keep the bowel functioning property 

(iii) Fiber helps in lowering of cholesterol level and regulates blood pressure 

(iv) They protect our muscles from cramping 

Q8: Lactose is disaccharide, which monosaccharides are presentation it?

Ans: In lactose, the monosaccharides glucose and galactose are present. 

C12H22O11 + H2O C6H12O6 + C6H12O6 

Q9: Why the Ten Amino Acids are essential for us? 

Ans: Because human body cannot synthesize essential amino acids. 

Q10: How Proteins are found? 

Ans: Two Amino acids link through peptide linkage. Peptide linkage is formed by the elimination of water molecule between the amino group of one amino acid and carboxyl group of another amino acid. 


R O R O R O R O 

H2N ― CH― C ―OH + HNH ― CH ― C ― OH H2N ― CH― C ― NH ― CH ― C ― OH 

Q11: How Gelatin is Obtained? 

Ans: Proteins are found in bones. Gelatin is obtained on heating bones. 

Q12: Give the General Formula of the Lipids? 

Ans: General Formula of Lipids is Triglyceride. 

OCH2 ― O ― C ― R O 

CH2 ― O ― C ― R 

O CH2 ― O ― C ― R 

Q13: Name Two Fatty Acids with their Formula? 

Ans: (a) Palmitic acid [C15H31COOH] (b) Stearic acid [C17H35COOH] 

Q14: Give the Types of Vitamins? 

Ans: Vitamins are Two types: - (a) Fat soluble vitamins (b) Water soluble vitamins 

Q15: What is the Significance of Vitamins? 

Ans: Human body is unable to synthesize vitamins. So, they must be supplied through diet, vitamins are 

absolutely necessary for our normal growth. They help to regulate our body’s metabolism. 

Q16: Describe the Sources and Uses of Vitamins A? 

Ans: Sources: Dairy products, egg, oil and fats, fish, beta carotene found in green vegetables, carrots and liver. 

Uses: It plays an important role in bone growth, tooth development, reproduction, cell division and gene expression. Also, the skin, eyes and mucous membranes of the mouth, nose, throat and lungs depend on Vitamin A. 

Q17: Deficiency of Vitamins K leads to which Disease? 

Ans: Vitamins K play an essential role in normal blood clotting. Its deficiency causes delay in blood clotting. 

Q18: Justify Water soluble Vitamins are not Injurious to Health? 

Ans: This is because water soluble vitamins are rapidly excreted from the body. Hence, they are not toxic even if taken in large quantity. 

Q19: What do you Mean by Genetic Code of Life

Ans: DNA is the permanent storage place for genetic information in the nucleus of a cell. It carries and stores all genetic information of the cell. It passes these information as instructions from generation to generation how to synthesize particular proteins from amino acids. These instructions are “Genetic Code of Life”. 

Q20: What is the Function of DNA? 

Ans: The sequence of nitrogenous bases in DNA determines the proteins development in new cells. The function of the double helix formation of DNA is to ensure that no disorder takes place. DNA carries genes that controls the synthesis of RNA. 

Q21: How you Justify RNA works like a Messenger? 

Ans: RNA consists of ribose sugar. It is a single stranded molecule. It is responsible for putting the genetic information to work in the cell build proteins. 


Q1: What is the importance of earth for our existence? 

Ans: There are four natural systems present on earth which are: - 

(i) Lithosphere. 

(ii) Hydrosphere. 

(iii) Atmosphere. 

(iv) Biosphere. 

Q2: Define Atmosphere? Name different layers of atmosphere 

Ans: “Atmosphere is the envelop of gases around the earth”. It is divided into four layers: - 

(i) Troposphere. 

(ii) Stratosphere. 

(iii) Mesosphere. 

(iv) Thermosphere. 

Nitrogen 78.09 % 

Oxygen 20.94 % 

Argon 0.93 % 

Carbon dioxide 0.03 % 

Name of region 

Height above the Earth’s 

Temperature range and trend 


0 ― 12 km 

17 ℃ ― -58℃ (decreases) 


12 ― 50 km 

-58 ℃ ― 2 ℃ (increases) 


50 ― 85 km 

2℃ ― -93 ℃ (decreases) 


85 ― 120 km 

> ― 93 ℃ (increases) 

(i) Volcanic eruption. 

(ii) Combustion of fossil fuels. 

(iii) Forest fires. 

(iv) Burning of wood. 

(v) Decomposition of organic matter. 

Q9: Why the 75% of the atmospheric mass lies within the troposphere? 

Ans: Troposphere is lower most region of atmosphere and extends up to 12 km, it forms major portion of atmosphere because it contain very large amount of gases. 

Q10: How ozone layer is being depleted by chlorofluro carbons? 

Ans: Ultraviolet radiations break the Cl ― Cl bond in CFCl3 and generates chlorine free radicals as: CFCl3 CFCl2 + Cl 

O3 + Cl O2 + Cl  OCl O + ClO + O O2 

Q11: What is function of Converter? 

Ans: Converter used by automobiles convert harmful CO and oxides of Nitrogen to harmless CO2 and N2 respectively, unburnt hydrocarbons are oxidized to Carbon dioxide and water while oxides of Nitrogen are reduced to nitrogen. 

Q12: Which Gases is life for Plant and Animal? 

Ans: CO2 is life gas for plant while O2 is life gas for animals. 

Q13: Taj Mahal has Stone Cancer Comments? 

Ans: Acidic gases from industrial units contribute to the wearing away of the famous marble building. Taj Mahal building is deteriorating by acid rain. 

Q14: CO2 is responsible for heating up Atmosphere? 

Ans: CO2 is green house gas. It absorbs infrared radiations and allows visible light to pass through. So, it absorbs most of outgoing radiations which result in heating of atmosphere. 

Q15: CO is a hidden enemy? Explain it action. 

Ans: It binds with haemoglobin of blood and forms carboxy haemoglobin. So, supply of oxygen is cut off. If inhaled for longer time it causes breathing difficulties which lead to death. 

Q16: What threats are to human health due to SO2 gas as air pollutant? 

Ans: It causes suffocation, irritation and severe respiratory problems to asthmatic people. 

Q17: Which air pollutant is produced in an anaerobic decomposition of Organic matter? 

Ans: CO2 is an air pollutant produced by anaerobic decomposition. 

Q18: How acid rain Increases the acidity of soil? 

Ans: Number of acids H2SO4, HNO3 and H2CO3 which are main components of acid rain comes on the surface of earth results in acidity of soil. 

Q19: Point out Two series Effects of Ozone Depletion? 

Ans: Two Effects of Ozone Depletion: 

(i) It causes skin cancer. 

(ii) Depletion of ozone layer will increase infections disease like malaria. 

Q20: How Ozone Layer forms in Stratosphere? 

Ans: Ozone layer is formed by the reaction of O2 and atomic oxygen. 

Q21: Define Incineration? 

Ans: Incineration is a waste treatments process that involves the burning of solid waste at high temperature. The temperature range from 650 to 100 ℃ in incinerators 

Q22: What is Importance of Incinerator? 

Ans: Incinerator reduces the solid mass of the original waste by 80-85% and converts waste material into ash, flue gas and heat. 

Q23: What is the Disadvantage of Incineration? 

Ans: Incineration produces highly poisonous gas and toxic ash. 

Q24: Without CO2 life on Earth would have been Impossible. Comment 

Ans: CO2 is the life gas for plant. It absorbs infrared radiations emitted by earth. So, life is not possible without CO2. 

Q25: Why there is a smell near photocopier machine? 

Ans: Ozone is well known as it is formed from oxygen near photocopier and other source of static electricity. There we smell ozone near these sources. It is poisonous gas and formed on hot day in badly polluted areas. 

Q26: What is difference between Pollutant and Contaminant? 

Ans: Pollutants are those substances which cause pollution while Contaminants are those substances that make some impure. 



Q1: How water rises in Plants? 

Ans: Water rises in plants by capillary action. This process is vital for the survival of plants. 

Q2: What is the difference Between Soft water and hard water? 

Ans: Soft Water 

Hard Water 

It is that water which produces good lather with soap. 

It is that type of water which does not produce good lather with soap. 

It does not give curd. 

It gives curds with soap. 

Example: It is free from Ca+2, Mg+2 ions. 

Example: Hard water contains Ca+2, Mg+2 ions. 

Q3: Which forces are Responsible for dissolving substance in Water? 

Ans: Dipole-Dipole forces are responsible for dissolving polar substances in water. 

Q4: Why Non-polar Compounds are Insoluble? 

Ans: Non-polar compounds have covalent bonds and they do not have polar ends. So, non-polar bonds are not attracted by water molecule. 

Q5: How water dissolve Sugar and Alcohol? 

Ans: Sugar and alcohol have polar ends i.e O¯ ― H⁺ group. These substances are soluble in water due to hydrogen bonding. 

Q6: How Lime Stone dissolve in Water? 

Ans: Limestone (CaCO3) is insoluble in water but small quantity of lime stone is soluble in water in the presence of CO2. It is shown as: 

CaCO3 + CO2 + H2O Ca(HCO3)2 

Q7: What is Softening of Water? 

Ans: The removal of Mg+2 and Ca2+ ions which are responsible for the hardness is called Water Softening. 

Q8: What are Types of Hardness of Water? 

Ans: There are two types of hardness of water: - 

(a) Temporary hardness (b) Permanent hardness 

Q9: What are the Causes of Hardness in Water? 

Ans: Dissolved salts of Mg+2 and Ca+2 with Cl-, SO4-2, HCO3-1 and CO32- causes hardness in water. 

CaCO3 + CO2 + H2O Ca(HCO3)2 

Q10: What is Water Pollution? 

Ans: Water pollution is a contamination of includes lakes, rivers, oceans and ground water. 

Q11: Describe Chlorination of Water? Give its Importance. 

Ans: It is the addition of chlorine solution in water. Chlorine kills bacteria and other micro-organisms. Chlorine itself does not kill rather it dissociate in water to form hypochlorous acid and hypochloric acid. 

Cl2 + H2O HOCl + Cl- + H+ 

HOCl turns ionize to produce hypochlorite and proton. So, 

HOCl H+ + OCl- 

Q12: What are Effects of Temporary of Detergents?

Ans: (i) Temporary hard water unfit for aquatic life. 

(ii) Insoluble calcium and magnesium carbonates reduce the efficiency of engine and boiler burst up. 

Q13: Mention Disadvantages of Detergents? 

Ans: (i) It makes water unfit for aquatic life. 

(ii) They cause diseases by microbes. 

(iii) They phosphates salts present in detergents cause rapid growth of algae. 

Q14: What is difference between biodegradable and non-biodegradable substances? 

Ans: Those substances that can be decomposed by micro organism like bacteria are called biodegradable substances and that substance that cannot be decomposed by ion is or organisms like bacteria are called non- biodegradable. 

Q15: How the detergents make the water unfit for aquatic life. 

Ans: Phosphate salts present in detergents cause rapid growth of algae. The plants die and decay. 

Q16: Why pesticides are used? 

Ans: Because they kill or control the growth of pests. Pests may be weeds, herbs, fungi and viruses. 

Q17: What are the reasons of water borne diseases? 

Ans: Diseases that spread because of drinking polluted water or eating food prepared with polluted water are called water born infectious diseases. 

Q18: How water borne disease can be prevented? 

Ans: Water borne diseases can be prevented by following measures: - 

(i) Provision of safe water. 

(ii) Disposal of sewage. 

(iii) Control of toxic chemicals. 

Q19: Define Soap? How can hard water reduce efficiency of soap? 

Ans: “Soap is the sodium salt of long chain carboxylic acids”. Example: Fatty acids. 

Calcium and magnesium ions of hard water react with soap to form insoluble precipitates of calcium and magnesium salts of fatty acid called scum. So, large amount of soap is washed in scum formation. Thus it decreases the efficiency of soap. 


Q1: What role is played by pine oil in the Concentration Process? 

Ans: The ore particles are preferentially wetted by oil and the gangue particles by the water. The whole mixture is agitated with compressed air. “Froth flotation process is based on the wetting characteristics of the ore and the gangue particles with oil and water, respectively”. 

Q2: Name the Various Metallurgical Steps? 

Ans: The Various metallurgical steps are: - 

(i) Concentration of the ore. 

(ii) Extraction of the metal. 

(iii) Refining of the metal. 

Q3: How Roasting is carried out? 

Ans: The process of heating concentrated ore to high temperature in excess of air. Following reaction: - 
2CuFeS2 Cu2S + 2FeS + SO 

Q4: Explain Process of Electro Refining? 

Ans: “Refining the impure metal by electrolysis is the most widely used process of refining metals.” 

Example: Electrolytic refining of copper is carried out in an electrolytic tank having copper sulphate solution in it. 

Q5: What are Advantages of Solvay’s Process? 

Ans: (i) It is cheap process as raw materials are available at very low price. 

(ii) Carbon dioxide and ammonia are recovered and reused. 

(iii) Sodium carbonate of very high purity is obtained. 

(iv) Consumption of fuel is very less since no solution is to be evaporated. 

Q6: What is the Principle of Solvay’s Process? 

Ans: Principle of solvay’s process lies in the low solubility of sodium bicarbonate at low temperature. 

Q7: What happens when Ammonical brine is Carbonated? 

Ans: Ammonical brine is fed into carbonating tower and carbon dioxide is passed through it. Following reactants take place in the carbonating tower. 

CO2 + NH3 + H2O NH4HCO3 

NH4HCO3 + NaCl NaHCO3 + NH4Cl CO2 + NH3 +H2O + NaCl NaHCO3 + NH4Cl 

Q8: How NaHCO3 is Converted to Na2CO3? 

Ans: Sodium bi carbonate is heated to get sodium carbonate. 

2NaHCO3 Na2CO3 + CO2 + H2O 

Q9: How ammonia is recovered in the Solvay’s process? 

Ans: Ammonia is recovered in Ammonia recovery tower from ammonium chloride solution and calcium hydroxide formed in lime kiln. 

2NH4Cl + Ca(OH)2 2NH3 + CaCl2 + 2H2O 

Q10: How ammonia is prepared for the synthesis of Urea? Ans: Ammonia is prepared by the “Haber’s Process”. 

N2 + 3H2 2NH3 

Q11: Describe the Formation of Petroleum? 

Ans: Petroleum was formed by the decomposition of dead plants and animals buried under earth’s crust millions of years ago. It is believed that millions of years ago living plants and animals in the seas died. Their bodies sank and buried under mud and sand. Then decomposition process took in the absence of air. Because of high pressure, temperature and bacterial effects remains of dead plants and animals were converted into a dark brownish viscous crude oil. 

Q12: What is Refining of Petroleum and how it is carried out? 

Ans: “Separation of crude oil mixture into various useful products”. It is carried out by a process called fractional distillation. The principal of fractional distillation is based upon separation of substance depending upon their boiling point. 

Q13: Give a Use of Kerosene Oil? 

Name Composition Boiling Range 

Diesel Oil  C13 to C15 250 to 350 C 

Fuel Oil  C15 to C18 350 to 400 C 

(i) Lubricants 

(ii) Paraffin wax 

(iii) asphalt 

(iv) Petroleum coke 

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