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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.
| 3651. |
Rakesh visited the government hospital to meet his cousin. He observed the medicine in dark bottles were not stored properly. They were not kept away from light and heat. Rakesh immediately reported the same to the medical superintendent and made sure that all medicines are stored properly. Why are some medicines stored at cool places in dark bottles ? |
| Answer» Solution :Some medicines when exposed to sunlight and HIGH temperature, their composition changes completely. Thus, to prevent the CHANGE in composition, they are stored at COOL places in DARK bottle. | |
| 3652. |
Rainwater is a precious natural resource. |
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Answer» |
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| 3653. |
Rahu, is studying in clas X whereas his younger brother Mohan is a student of clas VI. Mohan has been asked by his teacher to make a working model to show that some non-metal can also be a good conductor of electricity. Mohan has alreadymade an electric circuit by using a dry cell whose both the terminals are connected to two long copper wires having crocodile clips attached to their ends, and one of the copper wireshas a torch bulb connected in it through a bulb holder. Mohan, however failked to get a non-metal which could conduct electricity. Mohan asked his brother for help. Rahul told Mohan to take a pencil, sharpen this pencilat both ends, and then connect it in the circuit made by him attaching the two crocodile clips at its two ends. Mohan did the same. As soon as the pencil sharpened at both ends was connected in the circuit the torch bulb started glowing. (a) Of what substance is theblack core of pencil made? What does the glowing of bulb in this activity indicate? (b) Name the element of which the above substance is anallotrope? (c) Which allotrope of this element: (i) is used in glass cutters? (ii) is used in luibricating oils? (iii) has a spherical molecule made up of 60 atoms? (d) Name two properties of this element due to which it forms a large number of compounds. (e) Name one compound each of this element which is used: (i) as a solvent. (ii) to ripen raw fruits (iii) to preserve are displayed by Rahul in this episode? |
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Answer» Solution :(a) The black core of pencil is made of graphite (which is a form of carbon non-metal). The glowing of bulb indicates that graphite conducts electricity. In other works, no metal, carbon in the form of graphite is a GOOD conductor of electricity. (b) Carbon element (c) (i) Diamond (II) Graphite (iii) Buckminsterfullerene (d) (i) Catenation (self-linking) and (ii) Tetravalency (4 valency). (e) (i) Ethyl alcohol (or ETHANOL) (ii) Ethene (iii) Formaldelyde (in the form of its water solution called formalin). (F) The values displayed by Rahul in this episode are (i) Awareness (that pencil lead is made of graphite which isa good conductor of electricity) (ii) Desire to help his younger brother (iii) Knowledge of the allotropes of carbon, and (iv) Understanding of properties and uses of carbon compounds. |
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| 3654. |
Radha is a student of class X in a cityschool. One day Radha was doing practicals in the science laboratory of her school. Just then her science teacher, Mrs, Chopra, came to the laboratory with a beaker of a coourless solution. She told Radha that the colourless solution contains the nitrate of a metal which is usually alloyed with 24 carat gold to make 22 carat gold for ornaments. Mrs. Chopra asked Radha to device a method to obtain the dissolved metal from the solution in the solid form. Radha started thining about it. After some time Radha took a certain wire from the laboratory, cleaned it and placed it in the colourless solution in the beaker. She allowed this wire to remain immersed in the solution for a considerable time. Radha noticed a gradual change in the colour of solution in the beaker and saw a thick deposit of a substance on the wire kept in the solution. Radha was happy that she had done her job well. (a) Name the metal whose nitrate solutioin you think is given in the bearker? Why do you think so? (b)What was the nature of wire placed by Radha in the given solution? Why was this particular wire used? (c) What change in the colour of solution was obsered by Radha in the beaker and why? (d) Which substance was deposited on the wire placed in the solution? (e) Which chemical reaction is utilised by Radha in this process? Why does this reaction occur? (f) What values are displayed by Radha in this episode? |
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Answer» Solution :(a) The metal whose nitrate solution is given in the beaker is silver. That is the beaker contains silver nitrate solution (which is a colourless solution). Now, two metals silver and copper are usually alloyed with 24 carat pure gold to obtain 22 carat gold for making ORNAMENTS. Here the metal has to be silver because silver nitrate solution is colourless. On the other hand, copper nitrate solution would have been blue in colour. (b) The wire placed by Radha in silver nitrate solution was of copper metal. This is because copper is more reactive than silver and hence can displace silver from silver nitrate solution. (c) Radha observed that the colourless silver nitrate solution in the beaker gradually turned blue due to the formation of copper nitrate solution (which is blue in colour). (d) Silver metal present in dissolved form in the silver nitrate solution was deposited on the copper wire (in solid form). (e) Radha utilised THEDISPLACEMENT reaction of a metal with a salt solution. This displacement reaction occurs because copper is more reactive than silver due to which copper can displace silver from silver nitrate solution to form solid silver metal (which then deposites on copper wire). Some of the copper of copper wire passes into solution forming blue copper sulphate solution. (f) The VARIOUS VALUES displayed by Radha in this episode are (i) Awareness of alloys of gold (ii) Knowledge of rectivity series of metals (iii) Understanidng of displacement REACTIONS and (iv) Desire to complete the task given by her teacher. |
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| 3655. |
Quicklime reacts vigorously when treated with water and liberates a lot of heat energy . Which of the following statements is (are) incorrect about his reaction ? |
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Answer» The reaction is HIGHLY endothermic. |
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| 3656. |
Quick lime when added in water produces hissing sound. State the type of reaction. (i) Combination (ii) Endothermic (iii) Exothermic (iv) Redox |
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Answer» Only (i), |
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| 3658. |
Quantam theory of radiation was proposed by |
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Answer» Pauli |
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| 3660. |
purity of gold is expressed in ……….and …………. Is pure gold . |
| Answer» SOLUTION :CARAT. 24 carat GOLD | |
| 3663. |
Pure HCI is a bad conductor of electricity.Explain. |
| Answer» Solution :Pure HCL contains hydrogen chloride moleculesand no ions. Hence due to the ABSENCE of ions it is a BAD CONDUCTOR of ELECTRICITY. | |
| 3664. |
prove that aluminum is a powerful reducing agent . |
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Answer» Solution : Aluminium is a powerfful reducingagent. When a mixture a aluminium powder and iron oxide is IGNITED , iron oxideis reducedto iron , This processis Kownas aluminatherimcprocess `Fe_(2)O_(3)2AlRightarrow2Fe+Al_(2)O_(3)+ "HEAT"` |
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| 3666. |
Properties of the elements are given below. Where would you locate the following elements in thePeriodic Table? (a) A soft metal stored under kerosene. (b) An element with variable (more than one) valency stored under water. (c) An element which is tetravalent and forms the basis of organic chemistry, (d) An element which is an inert gas with atomic number 2. (e) An element whose thin oxide layer is used to make other elements corrosion resistant by the process of “anodising”. |
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Answer» SOLUTION :(a) Sodium (Na) Group 1 and PERIOD 3 or Potassium (K) Group 1 and Period 4 (b) PHOSPHORUS (P) Group 15 and Period 3 (c) Carbon (C) Group 14 and Period 2 (d) HELIUM (He) Group 18 and Period 1 (e) Aluminium (Al) Group 13 and Period 3 |
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| 3667. |
Properties of the elements are given below. Where would you locate the following elements in the periodic table? a] A soft metal stored under kerosene. b] An element with variable (more than one) valency stored under water. c] An element which is tetravalent and forms the basis of organic chemistry d] An element which is an inert gas with atomic number 2. e] An element whose thin oxide layer is used to make other elements corrosion resistant by the process of "anodising". |
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Answer» Solution :a) Because of high reactivity of ALKALI metals, they are usually kept under KEROSENE. Alkali metals are placed in group and start from periods 2 to 7. b] The element with variable valency stored under water is phosphorus. It shows a variable valency of 3 and 5 and is reactive towards air and not water. It is placed in group 15 and period 3 of periodic table. c) Carbon forms the basis of organic compounds. It exhibits tetravalency because it has 4 valence electrons. It is placed in group 14 and period 2 of Periodic table. d] Helium is the LIGHTEST inert gas with atomic number 2. It is placed in group 18 and period I of the periodic table. E] Aluminium metal is used to make other elements corrosion resistant by the process of "anodising". The oxide layer is of AI,O,. The atomic number of aluminium is 13 and it is placed in group 13 and period 3 of the periodic table. |
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| 3668. |
Properties of the elements mainly depend on their __________. (electronic configuration/atomic masses) |
| Answer» SOLUTION :ELECTRONIC CONFIGURATION | |
| 3669. |
Properties of the elements are a periodic function of their _______ . (atomic number/ mass number/relative atomic mass) |
| Answer» SOLUTION :ATOMIC NUMBER | |
| 3670. |
Propene is an unsaturated hydrocarbon. |
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Answer» |
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| 3671. |
Propene and propyne are _____ compounds |
| Answer» SOLUTION :UNSATURATED | |
| 3672. |
Propanone is an organic compound with functional group as |
| Answer» Answer :B | |
| 3673. |
Propanone has : |
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Answer» 7 COVALENT BONDS |
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| 3674. |
Producer gas is a mixture of |
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Answer» CARBON monoxide and nitrogen GAS `C + 1/2 O_2 + N_2 to CO+ N_2` |
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| 3675. |
{:("Process",," Ores"),("i.Hydraulic process",,"(a)ZnS"),("ii. Magnetic separation",,"(b)" Fe_(2)O_(3)),("iii. Froth floatation process",,"(c)"SnO_(2)),("iv. Leaching process",,"(d)" Al_(2)O_(3).2H_(2)O):} |
| Answer» SOLUTION :i-b, ii-c, iii-a, iv-d | |
| 3676. |
Probilty of finding a d_(yz) electron is zero along the |
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Answer» x-axis |
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| 3677. |
Pressure exerted by water vapour in moist gas is called __________ . |
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Answer» |
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| 3678. |
Preparation of zinc sulphate by the action of dilute sulphuric acid on zinc metal is called |
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Answer» DIRECT combination. |
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| 3679. |
Predict the nature of the bond in the following molecules. (i) NaCl (b) NaBr (c ) Nal (iv) NaF (v) NaH |
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Answer» Solution :(i) NaCl : Electronegativity difference between na and Cl is , 3 -1= 2 . That is grater than 1.7, therefore NaCl is iionic bond. (ii) NaBr : Electronegativity difference between Na and Br is , 2.8 - 1 = 1.8. That is greater than 1.7, therefore NaBr is ionic bond. (iii) Nal : Electronegativity difference between Na and I is, 2.5 - 1 = 1.5. That is lesser than 1.7, therefore NAI is COVALENT bond. (IV) NaF : Electronegativity difference between Na and F is , 4-1 = 3. That is greater than 1.7, therefore NaF is ionic bond. (V) NaH : Electronegativity difference between Na and H is, 2.1 -1 = 1.1 That is lesser than 1.7, therefore NaH is covalent bond. |
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| 3680. |
Predict the maximum number of valence electrons possible for atoms in the first period of the periodic table. |
| Answer» SOLUTION :The first period of the PERIODIC table has only two elements - hydrogen and helium-with atomic numbers 1 and 2. Hence, the atoms of elements in the first period of the periodic table can have a MAXIMUM of 2 valence ELECTRONS. | |
| 3682. |
Predict the formula of a compound formed between a metal 'M' that has 1st, 2nd, 3rd IP values as 518, 7314, 9820 kJ// mol, respectively and a halogen 'X'. |
| Answer» Answer :D | |
| 3683. |
Precipitation reactions do not produce insoluble salts. |
| Answer» SOLUTION :The WORD PRECIPITATION implies that an INSOLUBLE substance is produced. | |
| 3685. |
Pratyush took sulphur powder on a spatula and heated it. They collected the gas evolved by inverting a test tube over it, as shown in figure below. (a) What will be the action of gas on : (i) dry litmus paper ? (ii) moist litmus paper ? (b) Write a balanced chemical equation for the reaction taking place. |
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Answer» Solution :(a) (i) No change in colour of LITMUS paper. (II) The colour of litmus paper will turn RED because sulphor is non-metal and the oxides of non-metal are acidic in nature. (b) `S+O_(2) RARR SO_(2)` `SO_(2) + H_(2)O rarr H_(2)O_(4)` |
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| 3686. |
Pratyush took sulphur powders on a spatula and heated it. He collected the gas evolved by invertinv a test tube over it, as shown in figure below. a. What will be the action of gas on (i) dry litmus paper (ii) Moist litmus paper b. Write a balanced chemical equation for the reaction taking place. |
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Answer» Solution :(i) there will be no action on dry litmus PAPER. (ii) The colour of litmus paper will turn red because sulpher is a NON metal and the oxides of non metal are ACIDIC in nature. B. `S(s)+O_(2)(G)toSO_(2)(g)` |
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| 3687. |
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it. What will be the action of gas on (i) dry litmus paper? (ii) moist litmus paper (b) Write a balanced chemical equation for the reaction taking place. |
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Answer» Solution :When SULPHUR is heated in air, sulphur dioxide gas is formed. (i) Sulphur dioxide has no action on dry litmus paper. (II) Sulphur dioxide turns BLUE litmus paper to red. (B)`S(s)_(Sulphur) +O_2(G)_(Oxygen) to SO_2(g)_(Sulphur dioxide)` |
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| 3688. |
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by inverting a test tube over it as shown in figure below: (a) What will be the action of gas on (i) dry litmus paper ? (ii) moist litmus paper ? (b ) Write a balanced chemical equation for the reaction taking place. |
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Answer» Solution :When sulphur POWDER is heated in air, it forms sulphur dioxide, which is acidic in nature and its AQUEOUS solution is called sulphurous acid `(H_2SO_3)`. (a) Action of gas : (i) There will be no effect of gas on dry litmus PAPER. (II) Moist blue litmus paper changes its colour to red due to `H^+`ions present in the aqueous solution of `H_2SO_3` formed from `SO_2`obtained after burning sulphur. (b) BALANCED chemical equation for the above activity is as given below: `S(s) + O_2(g)toSO_2(g)` ` SO_2(g) + H_2O(l)underset("Sulphurous acid")(H_2SO_3(aq))` |
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| 3689. |
Pratyush took sulphur powder on a spatula and heated it. He collected the gas evolved by invertinga test tube over it as shown in Fig. below : (a) What will be the action of gas on (i) dry litmus paper ?(ii) moist litmus paper ?(b) Write a balanced chemical equation for the reaction taking place |
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Answer» Solution : (a) Sulphur is a non-metal. Oxides of non-metals are ACIDIC. In this case sulphur DIOXIDE is produced which is acidic. (i) There will be no action of the GAS on dry litmus paper. (ii) Wet litmus paper will TURN red. (b) The balanced chemical equation can be written as under : `S(s) + O_2(g) to SO_2(g)` |
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| 3690. |
Power alcohol is a mixture of………………. |
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Answer» ETHANOL + METHANE |
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| 3691. |
Powdered CaCO_(3)reactsmuch fasterwithHCl thanwith solidmarblechips. Accoundfor thefollowing . |
| Answer» SOLUTION :Powderingof THEREACTANTS INCREASES thesurfaceareaand moreenergyin collisionof reactantparticles. Thusthe reactionrateis INCREASED . | |
| 3692. |
Powdered …………….reacts more quikly with hydrochloric acid than marble chips. |
| Answer» SOLUTION :`CaCO_(3)` | |
| 3693. |
Powdered calcium carbonate reacts more readily with hydrochloric acid than marble chips.Why? |
| Answer» Solution :Powdering of the reactants INCREASES the surface area and more ENERGY is availble on collision of the reactant particles.Thus ,the reaction rate is inreased.Hence POWDERED calcium carbonate REACTS more readily with hydrochloric ACID than marble chips. | |
| 3694. |
Powdered CaCO_(3) reacts more rapidly than flaky CaCO_(3) because of…….. |
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Answer» Large SURFACE area |
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| 3695. |
Potato chips manufactures fill the packet of chips with nitrogen gas. Why ? |
| Answer» SOLUTION :It CUTS off OXYGEN and PROTECTS the food from RANCIDITY. | |
| 3696. |
Potassium chlorate (KClO_(3)) on heating forms potassium chloride and oxygen. Write a balanced equation for this reaction. |
| Answer» SOLUTION :`2KClO_(3)(s)rarr2KCl(s)+3O_(2)(G)` | |
| 3699. |
Position of three elements A, B and C in the periodic table is shown below : Giving reasons explain : (a) Element A is a metal. (b) Element B has larger atomic size than the element C. (c) Element C has a valency of one. |
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Answer» Solution :(a) Element A belongs to group I and period 3. It is sodium (NA) and is a metal. (b) We know that the atomic size of the ELEMENTS decreases along a period and increases down a group. The element B (group II and period 3) has larger atomic size than the element C (group II and period 2). (c) Element C is a member of halogen family. It is FLUORINE (F) and its valency is 1 (8 - 7 = 1). |
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