CBSE Class 12 Chemistry General Organic Chemistry Notes and Questions

VERY SHORT ANSWER TYPE QUESTIONS (1 Marks)

Question Q.1. What is slag?
Answer: It is an easily fusible material which is formed when gangue still present in roasted ore combines with the flux.
Example: \(\text{CaO (flux)} + \text{SiO}_2 \text{ (gangue)} \rightarrow \text{CaSiO}_3 \text{ (slag)}\)
In simple words: Slag is a waste glassy material formed when flux removes solid impurities from ore during smelting.

Exam Tip: Always remember the basic formula: Flux + Gangue = Slag.

Question Q.2. Which is better reducing agent at \(983\text{ K}\), carbon or \(\text{CO}\)?
Answer: Carbon monoxide (\(\text{CO}\)) is a better reducing agent below \(983\text{ K}\). Above \(983\text{ K}\), carbon (\(\text{C}\)) becomes a better reducing agent as it is more stable than \(\text{CO}\) at higher temperatures according to the Ellingham diagram.
In simple words: Below \(983\text{ K}\), \(\text{CO}\) reduces metal oxides better, but above \(983\text{ K}\), carbon takes over.

Exam Tip: Refer to the intersection point of the CO and C oxidation curves in the Ellingham diagram at \(983\text{ K}\).

Question Q.3. At which temperature carbon can be used as a reducing agent for \(\text{FeO}\)?
Answer: Above \(1123\text{ K}\), carbon can reduce \(\text{FeO}\) to \(\text{Fe}\).
In simple words: Carbon reduces iron oxide above \(1123\text{ K}\).

Exam Tip: Temperature threshold questions are direct; memorize \(1123\text{ K}\) for the reduction of \(\text{FeO}\) by carbon.

Question Q.4. What is the role of graphite rods in electrometallurgy of aluminium?
Answer: Graphite rods act as the anode in the Hall-Héroult process. They are attacked by oxygen evolved at the anode to form \(\text{CO}_2\) and therefore get consumed and need to be replaced from time to time.
In simple words: Graphite anodes burn away during aluminium extraction because they react with oxygen gas.

Exam Tip: State clearly that graphite acts as an anode and produces carbon dioxide gas.

Question Q.5. What is the role of cryolite in electrometallurgy of aluminium?
Answer: Alumina (\(\text{Al}_2\text{O}_3\)) has a very high melting point and is a poor conductor of electricity in solid form. Dissolving alumina in molten cryolite (\(\text{Na}_3\text{AlF}_6\)) lowers its melting point and increases electrical conductivity.
In simple words: Cryolite dissolves alumina and helps conduct electricity at lower temperatures.

Exam Tip: Mention both lowering of melting point and enhancing conductivity to get full marks.

Question Q.6. What are depressants?
Answer: Depressants are substances used in the froth flotation process to selectively prevent one of the components of a sulphide ore from forming froth, thereby allowing the separation of two sulphide ores.
Example: \(\text{NaCN}\) is used as a depressant to separate \(\text{ZnS}\) and \(\text{PbS}\); it selectively depresses \(\text{ZnS}\) while allowing \(\text{PbS}\) to come up in the froth.
In simple words: Depressants stop one specific mineral from floating so another can be separated easily.

Exam Tip: Always cite the classic example of sodium cyanide (\(\text{NaCN}\)) separating \(\text{ZnS}\) and \(\text{PbS}\).

Question Q.7. Copper can be extracted by hydrometallurgy but not \(\text{Zn}\). Why?
Answer: The standard reduction potential \(E^\circ\) of \(\text{Zn}\) is lower (more negative) than that of \(\text{Cu}\). Thus, \(\text{Zn}\) can displace \(\text{Cu}^{2+}\) ions from solution, but to displace zinc from zinc salt solution, we would need a metal more reactive than zinc.
In simple words: Zinc is more reactive than copper, so zinc can displace copper ions, but copper cannot displace zinc.

Question Q.8. Give name and formula of important ore of iron.
Answer: 1. Haematite: \(\text{Fe}_2\text{O}_3\)
2. Magnetite: \(\text{Fe}_3\text{O}_4\)
3. Iron pyrites: \(\text{FeS}_2\)
In simple words: Important iron ores include haematite and magnetite with their respective chemical formulas.

Exam Tip: Practice writing both the common mineral name and its exact chemical formula correctly.

Question Q.9. Give name and formula of important ore of copper.
Answer: 1. Copper pyrites: \(\text{CuFeS}_2\)
2. Malachite: \(\text{CuCO}_3 \cdot \text{Cu}(\text{OH})_2\)
3. Cuprite: \(\text{Cu}_2\text{O}\)
In simple words: Copper pyrites and malachite are prime ores of copper.

Exam Tip: Malachite formula contains both carbonate and hydroxide components.

Question Q.10. Give name and formula of important ore of zinc.
Answer: 1. Zinc blende: \(\text{ZnS}\)
2. Calamine: \(\text{ZnCO}_3\)
3. Zincite: \(\text{ZnO}\)
In simple words: Zinc blende and calamine are common zinc ores.

Exam Tip: Zinc blende (\(\text{ZnS}\)) is the principal commercial ore for zinc extraction.

SHORT ANSWER TYPE QUESTIONS (2 Marks)

Question Q.1. Describe the method of refining of nickel.
Answer: In the Mond Process, impure nickel is heated in a stream of carbon monoxide (\(\text{CO}\)) at \(330-350\text{ K}\) to form a volatile complex, nickel tetracarbonyl (\(\text{Ni}(\text{CO})_4\)). This complex is then decomposed at a higher temperature (\(450-470\text{ K}\)) to give pure nickel.
Reactions:
\(\text{Ni} + 4\text{CO} \xrightarrow{330-350\text{ K}} \text{Ni}(\text{CO})_4\)
\(\text{Ni}(\text{CO})_4 \xrightarrow{450-470\text{ K}} \text{Ni} + 4\text{CO}\)
In simple words: Impure nickel reacts with carbon monoxide to form a gas, which is then heated to deposit pure nickel metal.

Exam Tip: Mention the exact temperature ranges for carbonylation and decomposition steps.

Question Q.2. What is Zone Refining? Explain with example.
Answer: Zone refining is a method used for obtaining ultra-pure metals based on the principle that impurities are more soluble in the molten state of the metal than in the solid state. A moving circular heater melts a zone of an impure metal rod. As the heater moves along the rod, pure metal crystallizes out while impurities travel along with the molten zone to the end of the rod, which is then cut off.
Example: Purification of silicon, germanium, and gallium.
In simple words: Impurities travel with a moving melted zone along a metal bar, leaving pure metal behind.

Exam Tip: Emphasize the core principle: difference in solubility of impurities in molten versus solid states.

Question Q.3. Write the principle of electro-refining.
Answer: In electro-refining, the impure metal is made the anode and a thin strip of pure metal is made the cathode. An aqueous solution of a soluble salt of the metal is used as the electrolyte. On passing electric current, pure metal from the anode dissolves into the electrolyte and gets deposited at the cathode, while soluble impurities go into solution and insoluble impurities settle down as anode mud.
Example (Copper refining):
At Cathode: \(\text{Cu}^{2+} + 2e^- \rightarrow \text{Cu}\)
At Anode: \(\text{Cu} \rightarrow \text{Cu}^{2+} + 2e^-\)
In simple words: Pure metal transfers from the impure anode to the cathode through an electrolyte solution using electricity.

Exam Tip: Always specify anode, cathode, and what happens to impurities (anode mud).

Question Q.4. Write difference between calcination and roasting.
Answer: 1. Calcination involves heating the ore below its melting point in the absence or limited supply of air to expel volatile matter and moisture, and decompose carbonates. Roasting involves heating the ore in the regular presence of excess air below its melting point to oxidize impurities and convert sulphide ores into oxides.
2. Calcination is typically applied to carbonate and hydrated oxide ores, whereas roasting is applied to sulphide ores.
In simple words: Calcination heats ores without air to remove moisture/gases, while roasting heats ores with air to oxidize them.

Question Q.5. Describe the method of refining of Zirconium and Titanium.
Answer: The Van Arkel process is used for obtaining ultra-pure titanium and zirconium. The impure metal is heated with iodine in an evacuated vessel to form a volatile tetraiodide compound. The volatile metal iodide is electrically heated over a tungsten filament at a much higher temperature, decomposing it to deposit pure metal on the filament.
Reactions (for Zirconium):
\(\text{Zr (impure)} + 2\text{I}_2 \xrightarrow{850\text{ K}} \text{ZrI}_4\)
\(\text{ZrI}_4 \xrightarrow{2075\text{ K}} \text{Zr (pure)} + 2\text{I}_2\)
In simple words: Impure metal forms a volatile iodide gas, which is thermally decomposed on a hot filament to get pure metal.

Exam Tip: Remember the name 'Van Arkel Process' and the tungsten filament heating step.

Question Q.6. Out of C and CO, which is better reducing agent for \(\text{ZnO}\)?
Answer: Carbon (\(\text{C}\)) is a better reducing agent for \(\text{ZnO}\). Although the standard Gibbs energy of formation of \(\text{CO}\) from \(\text{C}\) drops below that of \(\text{ZnO}\) at higher temperatures, carbon acts directly as a solid reductant at smelting temperatures (\(1163\text{ K}\)) because the reduction line for zinc oxide lies above the carbon-to-carbon monoxide oxidation line in the Ellingham diagram.
In simple words: Carbon can reduce zinc oxide effectively at high temperatures in a retort furnace.

Question Q.7. The value of \(\Delta_f G^\circ\) for \(\text{Cr}_2\text{O}_3\) is \(-540\text{ kJ/mole}\) and that of \(\text{Al}_2\text{O}_3\) is \(-827\text{ kJ/mole}\). Is the reduction of \(\text{Cr}_2\text{O}_3\) possible with aluminium?
Answer: The desired reduction reaction is:
\(4\text{Al} + 2\text{Cr}_2\text{O}_3 \rightarrow 2\text{Al}_2\text{O}_3 + 4\text{Cr}\)
This can be obtained by combining the oxidation of aluminium and reduction of chromium(III) oxide:
\(4\text{Al} + 3\text{O}_2 \rightarrow 2\text{Al}_2\text{O}_3 \quad (\Delta G^\circ = -827\text{ kJ/mole})\)
\(2\text{Cr}_2\text{O}_3 \rightarrow 4\text{Cr} + 3\text{O}_2 \quad (\Delta G^\circ = +540\text{ kJ/mole})\)
Total \(\Delta G^\circ = -827 + 540 = -287\text{ kJ/mole}\).
Since the overall \(\Delta G^\circ\) is negative, the reduction of \(\text{Cr}_2\text{O}_3\) with aluminium is thermodynamically possible.
In simple words: Yes, because the net Gibbs free energy change for the reaction is negative.

Exam Tip: Add up the given free energy values carefully; a negative total \(\Delta G^\circ\) ensures spontaneity.

Question Q.8. Why copper matte is put in a silica-lined converter?
Answer: Copper matte consists of \(\text{Cu}_2\text{S}\) and \(\text{FeS}\). When a blast of air is passed through molten matte in a silica-lined converter, any remaining iron sulphide (\(\text{FeS}\)) is oxidized to iron(II) oxide (\(\text{FeO}\)), which then combines with the silica lining to form an easily fusible slag (\(\text{FeSiO}_3\)).
Reactions:
\(2\text{FeS} + 3\text{O}_2 \rightarrow 2\text{FeO} + 2\text{SO}_2\)
\(\text{FeO} + \text{SiO}_2 \rightarrow \text{FeSiO}_3 \text{ (slag)}\)
In simple words: The silica lining reacts with unwanted iron oxide impurities to remove them as slag.

Exam Tip: Always write both the oxidation of \(\text{FeS}\) and the slag-forming reaction with silica.

Question Q.9. What is meant by the term chromatography?
Answer: The word 'chromatography' is derived from Greek words meaning 'colour writing' because it was originally used for the separation of colored substances. It is a technique based on the selective distribution of various constituents of a mixture between two phases: a stationary phase and a moving (mobile) phase. The stationary phase can be either solid or liquid supported on a solid.
In simple words: Chromatography separates mixture components as they move at different rates through a stationary phase.

Exam Tip: Mention both stationary phase and mobile phase to score full credit.

Question Q.10. Why is reduction of metal oxide easier if metal formed is in liquid state at temperature of reduction?
Answer: The entropy of a substance is higher in the liquid state than in the solid state. In the reduction of a metal oxide, if the metal is formed in the liquid state, the entropy change (\(\Delta S\)) becomes more positive. This makes the term \(T\Delta S\) larger, leading to a more negative value of Gibbs energy change (\(\Delta G^\circ = \Delta H - T\Delta S\)), making the reduction occur more easily.
In simple words: Liquid metals have higher entropy, making the free energy change more negative and the reduction easier.

Exam Tip: Relate liquid state directly to higher entropy and a more negative \(\Delta G^\circ\).

SHORT ANSWER TYPE QUESTIONS (3 Marks)

Question Q.1. Explain the following:
(i) Zinc but not copper is used for recovery of Ag from the complex \([\text{Ag}(\text{CN})_2]^{-}\).
(ii) Partial roasting of sulphide ore is done in the metallurgy of copper.
(iii) Extraction of Cu from pyrites is difficult than that from its oxide ore through reduction.
Answer:
(i) Zinc is a more powerful and reactive reducing agent than copper, and it is also cheaper. It readily displaces silver from its cyanide complex.
(ii) Partial roasting of copper sulphide ore produces some copper oxide, which then reacts with remaining unroasted copper sulphide in the absence of air to undergo self-reduction into metallic copper and sulphur dioxide gas:
\(2\text{Cu}_2\text{S} + 3\text{O}_2 \rightarrow 2\text{Cu}_2\text{O} + 2\text{SO}_2\)
\(2\text{Cu}_2\text{O} + \text{Cu}_2\text{S} \rightarrow 6\text{Cu} + \text{SO}_2\)
(iii) Although carbon is a good reducing agent for metal oxides, it is a poor reducing agent for metal sulphides because the standard Gibbs energy of formation of metal sulphides is not sufficiently negative.
In simple words: Zinc reduces silver complexes easily, copper extraction uses self-reduction via roasting, and sulphides are harder to reduce directly with carbon than oxides.

Exam Tip: Address each sub-part clearly with chemical equations for self-reduction.

Question Q.2. Explain the method for obtaining pig iron from magnetite.
Answer: The extraction of iron from magnetite involves the following principal steps:
1. Concentration: Done by gravity separation followed by magnetic separation.
2. Calcination/Roasting: Heating the ore in air to remove moisture, volatile matter, and oxidize any ferrous oxide to haematite.
3. Smelting in a Blast Furnace: The roasted ore, coke, and limestone (\(\text{CaCO}_3\)) are charged into a blast furnace. Different reactions occur at various temperature zones:
- Zone of reduction (\(250^\circ\text{C}-700^\circ\text{C}\)):
\(3\text{Fe}_2\text{O}_3 + \text{CO} \rightarrow 2\text{Fe}_3\text{O}_4 + \text{CO}_2\)
\(\text{Fe}_3\text{O}_4 + \text{CO} \rightarrow 3\text{FeO} + \text{CO}_2\)
\(\text{FeO} + \text{CO} \rightarrow \text{Fe} + \text{CO}_2\)
- Zone of slag formation (\(800^\circ\text{C}-1000^\circ\text{C}\)):
\(\text{CaCO}_3 \rightarrow \text{CaO} + \text{CO}_2\)
\(\text{CaO} + \text{SiO}_2 \rightarrow \text{CaSiO}_3 \text{ (slag)}\)
- Zone of fusion (\(1150^\circ\text{C}-1350^\circ\text{C}\) and \(1450^\circ\text{C}-1950^\circ\text{C}\)): Carbon reduces to carbon monoxide and provides high heat.
The molten iron collected at the bottom is called pig iron.
In simple words: Iron ore is reduced with carbon monoxide and melted with limestone in a blast furnace to produce crude pig iron.

Exam Tip: Clearly categorize the blast furnace zones by their temperature ranges and specific chemical reactions.

Question Q.3. Describe the principles of extraction of copper from its ore.
Answer: Copper is mainly extracted from copper pyrites (\(\text{CuFeS}_2\)). The main steps involve:
1. Concentration: By froth flotation process.
2. Roasting: Heating the concentrated ore in excess air to remove moisture and volatile impurities, and partially convert sulphides to oxides.
3. Smelting: Melting roasted ore with coke and silica in a small blast furnace to form copper matte (mixture of \(\text{Cu}_2\text{S}\) and \(\text{FeS}\)) and iron silicate slag.
4. Bessemerisation: Blowing air through molten matte in a silica-lined converter to oxidize remaining iron and achieve self-reduction of copper sulphide to blister copper.
In simple words: Copper is extracted via froth flotation, roasting, matte smelting, and converter self-reduction.

Exam Tip: Outline the step-by-step sequence from froth flotation up to blister copper formation.

Question Q.4. Name the principal ore of aluminium and describe how Al is extracted from its ore.
Answer: The principal and commercially important ore of aluminium is Bauxite (\(\text{Al}_2\text{O}_3 \cdot x\text{H}_2\text{O}\)).
Extraction involves two main stages:
1. Purification of Bauxite (Leaching): Bauxite is digested with aqueous sodium hydroxide solution at \(473-523\text{ K}\) and \(35-36\text{ bar}\) pressure to dissolve alumina as sodium meta-aluminate, leaving insoluble impurities like \(\text{Fe}_2\text{O}_3, \text{TiO}_2\) and \(\text{SiO}_2\):
\(\text{Al}_2\text{O}_3 + 2\text{NaOH} + 3\text{H}_2\text{O} \rightarrow 2\text{Na}[\text{Al}(\text{OH})_4]\)
The solution is neutralized with \(\text{CO}_2\) gas to precipitate hydrated alumina, which is filtered and heated to get pure alumina (\(\text{Al}_2\text{O}_3\)):
\(2\text{Na}[\text{Al}(\text{OH})_4] + \text{CO}_2 \rightarrow \text{Al}_2\text{O}_3 \cdot x\text{H}_2\text{O} + 2\text{NaHCO}_3\)
2. Electrolytic Reduction (Hall-Héroult Process): Pure alumina is melted with cryolite (\(\text{Na}_3\text{AlF}_6\)) and fluorspar (\(\text{CaF}_2\)) in an electrolytic cell with carbon (graphite) electrodes.
At cathode: \(\text{Al}^{3+} + 3e^- \rightarrow \text{Al}\)
At anode: \(2\text{O}^{2-} \rightarrow \text{O}_2 + 4e^-\)
Aluminium is liberated at the cathode.
In simple words: Aluminium ore is purified using sodium hydroxide and then electrolyzed in molten cryolite to yield pure aluminium metal.

Exam Tip: Clearly separate the leaching process (Baeyer's process) from the electrolytic reduction step (Hall-Héroult process).

Question Q.5. Describe the principles of extraction of Zinc from zinc blende.
Answer: Zinc is extracted from zinc blende (\(\text{ZnS}\)) through the following steps:
1. Concentration: The crushed ore is concentrated by the froth flotation process followed by gravity separation.
2. Roasting: The concentrated zinc blende is roasted in the presence of excess air at a high temperature to convert zinc sulphide into zinc oxide:
\(2\text{ZnS} + 3\text{O}_2 \rightarrow 2\text{ZnO} + 2\text{SO}_2\)
3. Reduction: The resulting zinc oxide is mixed with powdered coke and clay, shaped into briquettes, and heated to around \(1163\text{ K}\). Carbon reduces zinc oxide to zinc metal, which distills off as a vapor and is collected by rapid cooling:
\(\text{ZnO} + \text{C} \rightarrow \text{Zn} + \text{CO}\)
In simple words: Zinc blende is roasted into oxide form and then reduced with coke by distillation to extract zinc metal.

Exam Tip: Mention the distillation step during the reduction of zinc oxide since zinc has a relatively low boiling point.

VERY SHORT ANSWER TYPE QUESTIONS (1 Marks) - CHEMISTRY IN EVERYDAY LIFE

Question Q-1. Define the term chemotherapy.
Answer: The treatment of diseases using chemical substances that have a therapeutic effect is called chemotherapy.
In simple words: Chemotherapy is curing diseases using specific medicinal chemicals.

Exam Tip: Keep the definition concise and focused on therapeutic chemical treatment.

Question Q-2. Why do we require artificial sweetening agents?
Answer: Artificial sweetening agents are required to reduce calorie intake or for diabetic patients who need to avoid sugar.
In simple words: They provide sweetness without adding extra calories or raising blood sugar.

Exam Tip: Mention calorie reduction and suitability for diabetic individuals.

Question Q-3. What are the main constituents of Dettol?
Answer: Chloroxylenol and terpineol.
In simple words: Dettol contains chloroxylenol and terpineol as its active antiseptic ingredients.

Exam Tip: Learn both spelling terms accurately for scoring.

Question Q-4. What type of drug is phenacetin?
Answer: Phenacetin is an antipyretic (reduces fever).
In simple words: Phenacetin is a fever-reducing medicine.

Exam Tip: Associate phenacetin directly with antipyretic action.

Question Q-5. Name the drug that is used to control allergy.
Answer: Antihistamines.
In simple words: Antihistamines stop allergic reactions in the body.

Exam Tip: Antihistamines block the action of histamine, the chemical causing allergy symptoms.

Question Q-6. Why is the use of aspartame limited to cold food and drinks?
Answer: Aspartame is unstable at cooking temperatures and decomposes when heated, losing its sweetness.
In simple words: Aspartame breaks down under heat, so it can only be used in cold foods.

Exam Tip: Mention thermal instability during cooking.

Question Q-7. What are tranquilizers? Give an example.
Answer: Tranquilizers are chemical compounds used for the treatment of stress, anxiety, or mild to severe mental diseases.
Example: Equanil or Luminal.
In simple words: Tranquilizers are calming drugs used to treat anxiety and mental stress.

Exam Tip: Always provide a standard example alongside the definition.

Question Q-8. What type of drug is chloramphenicol?
Answer: Chloramphenicol is a broad-spectrum antibiotic.
In simple words: Chloramphenicol fights a wide variety of bacterial infections.

Exam Tip: Classify it precisely as a broad-spectrum antibiotic.

Question Q-9. Why is bithionol added to toilet soaps?
Answer: Bithionol is added to act as an antiseptic to reduce the odor caused by bacterial decomposition of organic matter on the skin.
In simple words: Bithionol is added to soaps for its antiseptic properties to kill skin bacteria.

Exam Tip: State its antiseptic function clearly.

Question Q-10. What are food preservatives?
Answer: Food preservatives are substances that prevent the spoilage of food due to microbial growth.
Example: Sodium benzoate.
In simple words: Preservatives protect food from rotting and spoiling caused by microbes.

Exam Tip: Include sodium benzoate as a classic food preservative example.

SHORT ANSWER TYPE QUESTIONS (2 Marks) - CHEMISTRY IN EVERYDAY LIFE

Question Q-1. Mention one important use of the following: (i) Equanil (ii) Sucralose
Answer:
(i) Equanil: Used as a tranquilizer to relieve anxiety and stress.
(ii) Sucralose: Used as an artificial sweetener in foods and drinks.
In simple words: Equanil calms the mind, and sucralose sweetens food without calories.

Exam Tip: Clearly link each compound to its specific commercial application.

Question Q-2. Define the following and give one example: (i) Antipyretics (ii) Antibiotics
Answer:
(i) Antipyretics: Drugs that reduce body temperature during a fever.
Example: Paracetamol.
(ii) Antibiotics: Chemical substances produced by micro-organisms that inhibit or destroy other micro-organisms.
Example: Penicillin.
In simple words: Antipyretics lower fever, while antibiotics kill or stop bacteria.

Exam Tip: Provide both definition and example for each category.

Question Q-3. Name the medicines used for the treatment of the following: (i) Tuberculosis (ii) Typhoid
Answer:
(i) Tuberculosis: Streptomycin.
(ii) Typhoid: Chloramphenicol.
In simple words: Streptomycin treats tuberculosis, and chloramphenicol treats typhoid.

Exam Tip: Memorize these specific drug-disease pairings for objective questions.

Question Q-4. What is tincture of iodine?
Answer: A \(2-3\%\) solution of iodine in an alcohol-water mixture is called tincture of iodine. It is a powerful antiseptic and is applied on wounds.
In simple words: Tincture of iodine is an alcohol-based iodine solution used as a wound antiseptic.

Exam Tip: Remember the concentration range of \(2-3\%\) iodine in alcohol-water.

Question Q-5. What is an artificial sweetening agent? Give two examples.
Answer: Substances that provide a sweet taste to food without adding calories to our body are called artificial sweetening agents.
Examples: Saccharin, alitame.
In simple words: They make food sweet without adding calories or sugar.

Exam Tip: List common artificial sweeteners like saccharin or aspartame.

Question Q-6. How are synthetic detergents better than soaps?
Answer:
1. Synthetic detergents can be used effectively even in hard water, whereas soaps form insoluble precipitates (scum) in hard water.
2. Detergents generally possess a stronger cleansing action than soaps.
In simple words: Detergents work well in hard water and clean better than traditional soaps.

Exam Tip: Emphasize performance in hard water as the primary advantage.

Question Q-7. What are sulpha drugs? Give two examples.
Answer: A group of drugs that are derivatives of sulphanilamide and possess antibacterial activity, often used as early synthetic antibacterial agents, are called sulpha drugs.
Examples: Sulphadiazine, sulphanilamide.
In simple words: Sulpha drugs are synthetic antibacterial compounds related to sulphanilamide.

Exam Tip: Mention the sulphanilamide structural relationship.

Question Q-8. What forces are involved in holding the active sites of the enzymes?
Answer: The forces involved in holding substrate molecules at the active sites of enzymes include hydrogen bonding, ionic bonding, dipole-dipole attractions, and van der Waals forces of attraction.
In simple words: Various intermolecular forces hold substrates tightly to enzyme active sites.

Exam Tip: List all four types of non-covalent interactions for full marks.

Question Q-9. Describe the following giving an example in each case: (i) Edible colours (ii) Antifertility drugs
Answer:
(i) Edible colours: Food additives used to impart color and make food more attractive.
Example: Saffron used to color rice.
(ii) Antifertility drugs: Synthetic hormonal drugs used to control birth and prevent pregnancy.
Example: Norethindrone.
In simple words: Edible colors dye food, while antifertility drugs prevent pregnancy.

Exam Tip: Give clear examples for both food additives and medicinal drugs.

Question Q-10. Give two examples of organic compounds used as antiseptics.
Answer: Phenol (\(0.2\%\)) and iodoform.
In simple words: Phenol and iodoform are common organic antiseptic compounds.

Exam Tip: Specify phenol concentration (\(0.2\%\)) for antiseptic usage.

SHORT ANSWER TYPE QUESTIONS (3 Marks) - CHEMISTRY IN EVERYDAY LIFE

Question Q-1. What are biodegradable and non-biodegradable detergents? Give one example of each.
Answer:
- Biodegradable detergents: Detergents having a straight hydrocarbon chain that can be easily decomposed by micro-organisms.
Example: Sodium 4-(1-dodecyl)benzene sulphonate.
- Non-biodegradable detergents: Detergents having a branched hydrocarbon chain that cannot be easily decomposed by micro-organisms, leading to water pollution.
Example: Sodium 4-(1,3,5,7-tetramethyloctyl)benzene sulphonate.
In simple words: Straight-chain detergents break down easily in nature (biodegradable), whereas branched ones persist and pollute water.

Exam Tip: Highlight straight chain vs. branched chain structures as the key difference.

Question Q-2. What are barbiturates? To which class of drugs do they belong? Give two examples.
Answer: Derivatives of barbituric acid are called barbiturates. They belong to the class of tranquilizers and also act as hypnotics (sleep-inducing agents).
Examples: Luminal, seconal.
In simple words: Barbiturates are sleeping pills and calming agents derived from barbituric acid.

Exam Tip: Mention both tranquilizer and hypnotic functions.

Question Q-3. What is the use of: (i) Benadryl (ii) Sodium benzoate (iii) Progesterone
Answer:
(i) Benadryl: Used as an antihistamine.
(ii) Sodium benzoate: Used as a food preservative.
(iii) Progesterone: Used as an antifertility drug component / hormone.
In simple words: Benadryl stops allergies, sodium benzoate preserves food, and progesterone controls fertility.

Exam Tip: Match each pharmaceutical substance directly to its primary medical or household utility.

Question Q-4. Identify the type of drug: (i) Ofloxacin (ii) Aspirin (iii) Cimetidine
Answer:
(i) Ofloxacin: Antibiotic.
(ii) Aspirin: Analgesic and antipyretic.
(iii) Cimetidine: Antihistamine and antacid.
In simple words: Ofloxacin fights bacteria, aspirin relieves pain/fever, and cimetidine reduces stomach acidity.

Exam Tip: Cimetidine has dual properties (antihistamine that suppresses stomach acid production).

Question Q-5. Describe the following with a suitable example: (i) Disinfectant (ii) Analgesics (iii) Broad-spectrum antibiotics
Answer:
(i) Disinfectant: Chemical substances used to kill micro-organisms that are applied to non-living objects like floors and drainage systems.
Example: \(1\%\) phenol solution.
(ii) Analgesics: Drugs used to relieve pain without causing impairment of consciousness.
Example: Aspirin or ibuprofen.
(iii) Broad-spectrum antibiotics: Antibiotics that kill or inhibit a wide range of gram-positive and gram-negative bacteria.
Example: Chloramphenicol or ofloxacin.
In simple words: Disinfectants clean non-living surfaces, analgesics relieve pain, and broad-spectrum antibiotics kill many types of bacteria.

Exam Tip: Clearly differentiate disinfectants (non-living surfaces) from antiseptics (living tissues).