InterviewSolution
Saved Bookmarks
InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 5701. |
Give reason : Gold ornament do not lose their lusture. |
| Answer» SOLUTION :Gold is least REACTIVE and hence doesn.t REACT | |
| 5702. |
Give reason for the following : (i) Metals conduct electricity. (ii) Reaction of nitric acid with metals generally does not evolve hydrogen gas. (iii) For making gold ornaments, 22 carat gold is preferred to 24 carat gold. |
|
Answer» Solution :(i) Metals conduct electricity because they have electrons which are free to MOVE. They offer little resistance to the flow of current. (ii) Reaction of metals with nitric acid does not evolve hydrogen gas. It is because `HNO_(3)` is a strong OXIDISING AGENT. It oxidises `H_(2)` to PRODUCE water and itself gets reduced to any of its oxides such as `N_(2)O`, NO or `NO_(2)`. (iii) Pure gold is 24 carat and is very soft. Therefore, it is not suitable for making jewellery. it is alloyed with Cu or Ag to mae it hard. Generally, 22 carat gold is used for making ornaments, which contains 22 parts of pure gold and 2 parts of either Cu or Ag. |
|
| 5703. |
Give reason for the following : (i) Ionic compound have high melting and boiling points. (ii) Ionic compounds are soluble in water. (iii) Ionic compounds conduct electricity in molten state. |
|
Answer» Solution :(i) ionic compounds have high MELTING and boiling points. In is because of strong force of attraction between oppositely charged ions, therefore high energy is required to break the metallic bonds between ions. (ii) Ionic compounds are soluble in water because they form ions in aqueous solutions. (iii) Ionic compounds conduct electricity in molten state and in aqueous solution because ions carry current. The MOVEMENT of ions takes place towards oppositely charged electrode in electric field. |
|
| 5704. |
Give reason for the following : (i) Aluminium is a reactive metal but is still used for packing food articles. (ii) Calcium starts floating when water is added to it. |
|
Answer» Solution :(i) Because it forms a protective oxide LAYER around itself preventing complete REACTION and also does not effect the food at all. (ii) CALCIUM floats over water because the BUBBLES of HYDROGEN gas formed sticks on the surface of the metal. |
|
| 5705. |
Give reason for the following: a) Metals are regarded as electropositive elements. b) When a piece of copper metal is added to a solution of Zinc sulphate, no change take place, but the blue colour of copper sulphate fades away when a piece of zinc is placed in its solution .c) Articles of aluminium do not corrode even though alluminium is an active metal. |
|
Answer» Solution :a) Metals have a tendency to lose one or more electrons to form positive ions. Therefore, metals are called electropositive ELEMENTS. Copper is less reactive than Zinc. Therefore, if cannot displace Zinc from `ZnSO_4`solution. But Zinc being more reactive than copper, it DISPLACES copper from `CuSO_4` solution. As a result the concentration of `Cu^(2+)`ions fall and blue COLOUR fades. ` Zn(s) + underset("blue")(CuSO_4(aq) )to underset("colourless")(ZnSO_4 (aq) ) + Cu(s)` c) ALUMINIUM being a reactive metal readily combines with OXYGEN to give a protective layer of `AI_2O_3`. As a result further corrosion stops. |
|
| 5706. |
Give reason for the following:(a) Sodium is kept immersed in kerosene oil. (b) Iron, the most widely used metal, is never used in its pure state. (c) Hydrogen is not evolved when a metal reacts with nitric acid (except Mn and Mg). |
|
Answer» Solution : (a) Sodium is a reactive metal. It reacts both with air and water. `NA + 2H_2Oto NAOH + H_2` Kerosene does not react with sodium. (b) Iron is a soft metal. It is alloyed with other elements for different uses. (c) This is because hydrogen gas FIRST evolved reacts with `HNO_3`to FORM OXIDES of nitrogen. |
|
| 5707. |
Give reason : Carbonate and Sulphide ores are usually converted into oxides during the process of extraction. |
| Answer» Solution :Carbonate and SULPHIDE ORES are USUALLY converted into oxides during the PROCESS of extraction because metals can be easily extracted rather than from their carbonate and SULPHIDES. | |
| 5708. |
Give reasons: a. Platinum, gold, and silver are used to make jewellery. b. Sodium, potassium, and lithium ar stored under oil. c. Aluminilum is a higly reactive metal, yet it is used to make utensils for cooking. d. Carbonate and sulphate ores are usually convertedinto oxides during metal extraction. |
| Answer» Solution :Platinum, gold and silver are used to make JEWELLERY because they are very LUSTROUS. Aslo they are very less reactive and do not CORRODE easily. | |
| 5709. |
Give reactions of calcium and magnesium with dilute nitric acid. |
|
Answer» SOLUTION :`Ca+2HNO_(3)rarrCa(NO_(3))_(2)+H_(2)` `Mg+2HNO_(3)rarrMg(NO_(3))_(2)+H_(2)` |
|
| 5710. |
Give reaction of calcium and magnesium with dilute nitric acid. |
|
Answer» SOLUTION :(i) `Ca+2HNO_(3)toCa(NO_(3))_(2)+H_(2)` (ii) `Mg+2HNO_(3)toMg(NO_(3))_(2)+H_(2)` |
|
| 5712. |
Give one example of each of the following: Soluble salt |
| Answer» SOLUTION :SODIUM CHLORIDE, NACL | |
| 5713. |
Give one example of each of the following: Normal salt |
| Answer» SOLUTION :SODIUM CHLORIDE, NACL | |
| 5714. |
Give one example of each of the following: Insoluble salt |
| Answer» SOLUTION :BARIUM SULPHATE, `BaSO_(4)` | |
| 5715. |
Give one example of each of the following: A metal hydroxide which is highly soluble in water. |
| Answer» SOLUTION :POTASSIUM HYDROXIDE, KOH | |
| 5716. |
Give one example of each of the following: Hydrated salt |
| Answer» Solution :Copper sulphate, `CuSO_(4)*5H_(2)O` | |
| 5717. |
Give one example of each of the following: A basic oxide which is insoluble in water. |
| Answer» SOLUTION :CALCIUM OXIDE, CAO | |
| 5718. |
Give one example of each of the following: A basic oxide which is soluble in water. |
| Answer» SOLUTION :SODIUM OXIDE, `Na_(2)O` | |
| 5719. |
Give one example of each : (a) Metal having valency 2. (b) Non-metal having valency 2. (c) Element with three shells, having 4 electrons in the outermost shell. |
|
Answer» Solution :(a) Magnesium has a valency of 2. (B) SULPHUR has a valency of 2. (c) Silicon has three SHELLS having 4 electrons in the outermost shell (2, 8, 4). |
|
| 5720. |
Give one example of decomposition reaction in which solid and gas are formed as products. |
| Answer» Solution :`CaCO_(3) OVERSET(Delta)to CaO(s)+CO_(2)(g)` | |
| 5721. |
Give one example of a reaction which is a double displacement reaction as well as a precipitation reaction. |
| Answer» Solution :`underset("Silver nitrate")(AgNO_(3)(aq))+underset("Sodium chloride")(NACL(aq))rarrunderset("Silver chloride (PPT.)")(AGCL(s)darr)+underset("Sodium nitrate")(NaNO_(3)(aq))` | |
| 5722. |
Give one example of a combination reaction which is also exothermic. |
|
Answer» Solution :When quicklime or calcium oxide (CaO) reacts with water, slaked LIME `[Ca(OH)_(2)]` is formed. During this reaction a large amount of heat is released. So, this reaction is an EXOTHERMIC reaction. `UNDERSET(("Quicklime"))underset("Calcium oxide")(CaO(s))+underset("Water")(H_(2)O(L))rarrunderset(("Slaked lime"))underset("Calcium hydroxide")(Ca(OH)_(2)(aq))+"Heat"` |
|
| 5723. |
Give one example of a combination reaction in which an element combines with a compound to give you a new compound. |
| Answer» SOLUTION : `O_(2)2SO_(2) to 2SO_(3), 6NH_(3)+3Cl_(2) to 5NH_(3)CL` | |
| 5724. |
(a) Give a chemical test to distinguish between saturated and unsaturated hydrocarbon. (b) Name the products formed when ethane burns in air. Write the balanced chemical equatioin for thereaction showing the types of energies liberated. (c) Why is reactiion between methane and chlorine in the presence of sunlight considered a substitution reaction ? |
| Answer» SOLUTION :UNSATURATED HYDROCARBONS decolourise BROMINE solution but SATURATED hydrocarbons do not. | |
| 5725. |
Give one chemical test to distinguish between the Ethyne and ethene |
| Answer» SOLUTION :ETHYNE GIVES a white preicipitate with ammoniacal solution of silver nitrate and a red precipitate with copper (I) chloride, whereas ETHENE does not | |
| 5726. |
Give one chemical test to distinguish between the Ethyne and ethanol |
| Answer» SOLUTION :ETHYNE gives a white preicipitate with ammoniacal solution of SILVER NITRATE and a red precipitate with COPPER (I) chloride, whereas ethanol does not. | |
| 5727. |
Give one chemical test to distinguish between the Ethanoic acid and ethanol |
| Answer» SOLUTION :ETHANOIC acid turns BLUE litmus red and LIBERATES carbon DIOXIDE from carbonates, whereas ethanol does not. | |
| 5728. |
Give one chemical test to distinguish between the Alkanes and alkenes |
| Answer» SOLUTION :ALKENES decolourise BROMINE solution but ALKANES do not. | |
| 5729. |
Give one chemical test to distinguish between theEthane and ethyne |
| Answer» SOLUTION :ETHYNE DECOLOURISES BROMINE solution but ETHANE does not. | |
| 5730. |
Give one chemical test to distinguish between theEthane and ethene |
| Answer» Solution :Ethene DECOLOURISES BROMINE solution and alkaline potassium permanganate, whereas ETHANE does not | |
| 5731. |
Give one chemical test to distinguish between the Alkenes and alkynes |
| Answer» Solution :ALKYNES GIVE white PRECIPITATE with ammoniacal solution of SILVER nitrate but alkenes do not. | |
| 5732. |
Give ionic definition of a salt. |
| Answer» Solution :SALT is a substance which contains CATIONS and ANIONS other than `H^(+)andOH^(-)`. | |
| 5733. |
Give important uses of Plaster of Paris. |
|
Answer» Solution :1. Plaster of Paris is used for producing moulds for toys, pottery, ceramics, etc. 2. It is used for making statues, models and other decorative MATERIALS. 3. It is used in medical applications known as plasters for SETTING broken and fractured bones in the right position and in dentistry. 4. It is used for making smooth surfaces and ornate designs on walls and ceilings. 5. It is used as a fire proofing material. 6. It is used in LABORATORIES for sealing the air gaps in apparatus to make it air tight. |
|
| 5734. |
Give important properties of ethanoic acid (Acetic acid). |
|
Answer» Solution :Important properties of monocarboxylic ACID. 1. Ethanoic acid or acetic acid is colourless liquid and is soluble in water, 5-8% solution of acetic acid in water is called VINEGAR. 2. PURE ethanoic acid melts at 290 K and freezes during winter in cold climates and looks like ice. Hence it is called glacial acetic acid. 3. Esterification. When an acid is heated with an alcohol in the presence of conc. `H_(2)SO_(4)`, an ester is produced. Thus is a slow reversible reaction and is called esterification. e.g. `underset(("Ethanoic acid"))(CH_(3)COOH) + underset(("Ethanol"))(C_(2)H_(5)OH)` Esters are sweet-smelling substances. 4. Action with a base `underset("Acetic acid")(CH_(3)COOH) + NaOH rarr underset("Sodium acetate")(CH_(3)COONa) + H_(2)O` 5. Action with carbonates and bicarbonates. Ethanoic acid decomposes carbonates and bicarbonates producing salt, carbon dioxide and water. `2CH_(3)COOH + Na_(2)CO_(3) rarr 2CH_(3)COONa + H_(2)O + CO_(2) uarr` `CH_(3)COOH + NaHCO_(3) rarr CH_(3)COONa + H_(2)O + CO_(2) uarr` |
|
| 5735. |
Give four uses of bleaching powder. |
|
Answer» Solution :1. It is used for bleaching COTTON and linen in the textile industry. 2. It is used for bleaching WOOD PULP in paper factories. 3. It is used for disinfecting DRINKING water. 4. It is used as an oxidising agent in many chemical INDUSTRIES. |
|
| 5736. |
Give examples of two mixtures. |
| Answer» Solution :The TWO EXAMPLES are (a) a mixture of soil and water, and (b) a mixture of iron FILINGS and SULPHUR. | |
| 5738. |
Give examples of corrosion. |
| Answer» Solution :Examples of corrosion are as follows :Silver ARTICLES become BLACK after some time when exposed to air. This is because it reacts with sulphur in the air to FORM a coating of silver sulphide. Copper reacts with moist carbon dioxide in the air and slowly loses its SHINY brown surface and gains a green coat. This green substance is basic copper carbonate. Iron when exposed to moist air for a long time acquires a coating of brown flaky substance called rust. | |
| 5739. |
Give examples for deliquescent substances |
|
Answer» SOLUTION :CALCIUMCHLORIDE`(CaCl_2)` 2.causticsoda`(NAOH )` 3.Causticpotsh (KOH )4.Ferricchloride `(FeCl_3)` |
|
| 5740. |
Give chemical name and formula of bleaching powder. What happens when it is exposed to air ? Mention two uses of bleaching powder. |
|
Answer» Solution :Chemical name of bleaching powder is CALCIUM oxychloride. `CaOCl_(2)` On exposure to air, it absorbs MOISTURE, Uses: (i) As an oxidising agent in chemical industries. (ii) Which soutions has the lowest concentration of `H^+` IONS ? |
|
| 5741. |
Give chemical equation to show the changes that occur when green coloured ferrous sulphate crystals are heated. Mention the change observed as well as reason for this change. |
|
Answer» SOLUTION :`2FeSO_4 to^(Heat) Fe_2O_3+SO_2+SO_3` CRYSTALS loose their colour , DUE to LOSS of water of CRYSTALLIZATION on heating. |
|
| 5742. |
Give chemical equation for the reaction of aluminium powder with maganese dioxide on heating. |
| Answer» Solution :`3MnO_(2)(s) + 4AL(s) overset(Delta)RARR 3Mn(L) + 2Al_(2)O_(3)(s) + "Heat"` | |
| 5743. |
Give any twouses of aluminum. |
| Answer» SOLUTION : (i)Aluminum metal is a corrosion RESISTANT and a GOOD CONDUCTOR of heat.So it is used in making UTENSILS.(ii) Aluminum is used in welding as thermite and a very good reducing agent. | |
| 5744. |
Give any two examples for heterodiatomic molecules. |
| Answer» SOLUTION :Heterodiatomic MOLECULES - e.g., `HCL, NACL` | |
| 5745. |
Give any two applications of Avogadro's law. |
|
Answer» Solution :Avogadro.s law : EQUAL volumes of all gases under the same conditions of temperature and pressure contain an equal number of molecules. Applications of Avogadro.s law : It is used to DETERMINE the atomicity of gases. It is helpful in determining the molecular formula of gaseous COMPOUNDS. It establishes the relationship between the vapour DENSITY and molecular mass of a gas. It gives the value of molar value of molar volume of gases at STP. Molar volume of a gas at STP = 22.4 LITRES. It explains Gay lussac.s law effectively. |
|
| 5746. |
Give any three uses of ethanoic acid. |
|
Answer» Solution :Uses of ethanoic acid : 1. Ethanoic acid is used in the manufactured of DYES perfumes and rayon. 2. It is used in the manufacture of plastics, rubber and silk INDUSTRIES. 3. It is used as a vinegar in cooking as food DRESSING and for PREPARING pickles. |
|
| 5747. |
Give any four uses of ehtyl alcohol in daily life. |
|
Answer» Solution :(i) It is used as an antiseptic to sterlize wounds and SYRINGES in hospitals. (ii) it is used as an antifreeze in CAR radiators. (iii) It is used as fuel in spirit lamps and internal combustion engines. (iv) It is used in making alcoholic DRINKS e.g. whisky, wine, beer, etc. |
|
| 5748. |
Give an outline of the processes involved in the conversion of ethanoic acid into methane. |
| Answer» SOLUTION :`underset(" ETHANOIC acid")(CH_(3))COOH_ overset(NaOH)to underset(" Sodium ehtanoate")(CH_(3)COONA) overset(" sodalime") underset("heat")to underset(" MEHTANE") (CH_(4))` | |
| 5749. |
Give an example to explain a skeletal and a balanced chemical equation. |
|
Answer» Solution :Skeletal equation - It is an unbalanced CHEMICAL equation, where the number of atoms of REACTANTS and products unequal. e.G. `H_(2)+Cl_(2)toHCl`. Balanced equation - It is a chemical equation where the number of atoms of reactants and products equal. It also indicates the conditions of the REACTION and the states of the reactants and products formed. e.g. : `H_(2)(g)+Cl_(2)(g)to2HCl(g)`. |
|
| 5750. |
Give an example of redox reaction, naming the substances which are oxidised and reduced. |
Answer» SOLUTION :
|
|