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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.
| 8351. |
A solid compound 'A' decomposes on heating into'B' and a gas 'C' .On passing the gas 'C' through water,it becomes acidic .Identify A,B and C. |
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Answer» Solution :`underset(("A"))(CaCO_(3(s)))tounderset("(B)")(CaCO_((s)))+underset("(C)")(CO_(2(g)))` CALCIUM carbonate decomposes into solid calcium OXIDE and a GAS `CO_(2)` This `CO_(2)` dissolves in water and forms carbonic acid. `H_(2)O+underset("(C)")(CO_(2))tounderset("Carbonic acid")(H_(2)CO_(3))` |
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| 8352. |
A solid compound 'A' consists of simple ions. Choose corresponding answers from the choices given below. Natural of the bond present in A will be |
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Answer» IONIC |
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| 8353. |
A small amount of soil mixed with pure water. The process you can apply to recover pure water from the mixture is |
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Answer» decantation |
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| 8354. |
A small amount of quick lime is added to water in a beaker. (i) Name and define the type of reaction that has taken place. (ii) Write the balanced equation for the reaction and chemical names of the product formed. (iii) List two main observations in the reaction. |
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Answer» Solution :(i) It is combustion reaction - A reaction in which TWO or more elements or compounds is called COMBINATION reaction (ii) `CaO(s)+H_(2)O(l)toCa(OH)_(2)(aq)"CALCIUM hydroxide"`. (iii) OBSERVATION : (i) hissing sound is produced (ii) Solution becomes hot because heat is evolved. |
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| 8355. |
A small amount of quick lime is added to water in a beaker. Write balanced chemical equation for the above reaction. Write the chemical name of product obtained. |
| Answer» SOLUTION :`UNDERSET("Calcium OXIDE")(CaO(s))+H_(2)O(l)tounderset("Calcium hydroxide")(CA(OH)_(2)(aq))` | |
| 8356. |
A small amount of quick lime is added to water in a beaker. State two observations that you will make in the reaction. |
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Answer» SOLUTION :(i) Quick lime reacts vigorously with water PRODUCING calcium hydroxide. (ii) A large AMOUNT of heat is PRODUCED. |
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| 8357. |
A small amount of quick lime is added to water in a beaker. Name and define the type of reaction that has talen place. |
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Answer» Solution :It is a COMBINATION REACTION. When two more REACTANTS combine to give single PRODUCT, it is termed as combination reaction. |
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| 8358. |
A small amount of hydrochloric acid is added to water. Which of the following about this is (are) correct ? |
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Answer» Hydrochloric acid gets ionized |
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| 8359. |
A small amount of ______ is added to pure gold for making jewellery. |
| Answer» SOLUTION :SILVER, JEWELLERIES | |
| 8360. |
A small amount of copper oxide is taken in a test tube and dilute acid is added to it with stirring. Which colour will be obtained in the test tube ? |
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Answer» Blue-green |
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| 8361. |
A small amount of calcium oxide is taken in a breker and water is added slowly to it. (i) Will there be any changein temperature of the contents ? Explain. (ii) Name and define the type of reaction taking place (iii) Write chemical equation for the above reaction . |
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Answer» Solution :(i) Yes, TEMPERATURE rises as the beaker GETS hot. This is because large amount of heat is released or the reaction is exothermic. (ii) Combination reaction . Reaction in which a single products is obtained from two or more reactants . (III) `underset (("Quick lime")) (CAO)+H_(2)Orarrunderset(("Slaked lime"))(CA(OH)_(2))+"heat"` |
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| 8362. |
A slow combustion in which glucose present in the body cells combine with oxygen to provide energy is |
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Answer» Digestion |
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| 8363. |
A single displacement reaction is represented byX_((s))+2HCl_((aq))toXCl_(2(aq))+H_(2(g)) . Which of the following (s) could be X? (i)Zn (ii)Ag (iii)Cu (iv)Mgchoose the best pair. |
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Answer» I and ii `Mg+2HCltoMgCl_(2)+H_(2)` |
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| 8364. |
A singledisplacementreaction is representedbyX_((s)) +2HCl _((aq)) to XCl_(2((aq)) +h_(2(aq)).whichof thefollowing(s)couldbex?(i) Zn(ii) Ag (iii )Cu(iv )Mg. Choosethe bestpair . |
| Answer» Answer :D | |
| 8365. |
A silvery white metal on treatment with NaOH and HCl liberated H_(2) gas to form B and C respectively , the metal A will not react with acid D due to the formation of a passive film on the surface . Hence it is used for transporating acid D. Identify A, B, C, D and support your answer with balanced equations. |
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Answer» Solution : A silvery white metal metal (A) is aluminium (Al) (ii) Aluminium REACTS with NaOH to form B which is known as sodium meta aluminate with the liberation of `H_(2)` gas (iii) Aluminium reacts with HCl to form aluminium chloride which is known as C with the liberation of `H_2)` gas . `2Al+6HClrightarrow2AlCl_(3)+3H_(2)uparrow` (iv) Aluminium deos not react with conc.nitric acid `(HNO_(3)` Which is known as D, due to the formation of a passive FLN on the surface 
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| 8367. |
A silver ornament remained exposed to the atmosphere for a long time. The colour of its surface looked |
| Answer» Solution :Silver reacts with OXYGEN to FORM `Ag_(2)O` Which is black in colour. | |
| 8368. |
A silver article generally turns black when kept in the open for a few days. The articles when rubbed with toothpaste again starts shining. (i) Why do they turn black ? Name the phonomenon involved. (ii) Name the black substance formed and write its formula. |
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Answer» Solution :(i) Silverarticle reacts with SULPHUR compounds such as `H_(2)S` PRESENT in air . The phenomenon is CALLED corrosion. For silver PARTICULARLY, it is called tranishing of silver. (ii) The black substance is islver sulphide `(Ag_(2)S)`. |
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| 8370. |
(a) Show the formation of Na_2Oby transfer of electrons between the combining atoms.(b) Why are ionic compounds usually hard ? (c) How is it that ionic compounds in the solid state do not conduct electricity and they do so when in molten state ? |
Answer» Solution :(a) FORMATION of `Na_2O`is shown below : (b) Ionic COMPOUNDS are usually hard because of strong force of ATTRACTION between the IONS. (c) Due to rigid structure in the solid state, movement of ions is not possible. HENCE, ionic compounds do not conduct electricity in the solid state. In the molten state, ions become mobile and conduct electricity. |
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| 8371. |
A shorthand representation of a chemical reaction is known as the chemical equation. |
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Answer» |
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| 8372. |
A shiny brown coloured element .X. on heating in air becomes black in colour. Name the element .X. and the black coloured compound formed. |
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Answer» Solution :Here, element .X. is COPPER (CU). When it is HEATED in air, it forms black coloured copper OXIDE (CuO). For example `underset("Brown Coloured shiny element")(2Cu)+O_(2) overset(Delta)to underset("Black coloured compound")(2CuO)` In this reaction, Cu is oxidised to CuO. |
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| 8373. |
A shiny brown coloured element 'X' on heating in air becomes black in colour. Name the element 'X' and the black coloured compound formed. |
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Answer» Solution :The BROWN coloured element .X. is COPPER. On HEATING in air it FORMS copper oxide which is black in colour. `UNDERSET("(Brown colour)")underset("Copper")(2Cu(s))+underset("Oxygen")(O_(2)(g))tounderset("(Black)")underset("Copper oxide")(2CuO(s))` |
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| 8374. |
A shiny brown -coloured elemnt 'X' on heating in air becomes black in colour. Name the element 'X' and the black - coloured compound formed. |
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Answer» Solution :X . is COPPER (CU) and the black-coloured compound formed is. copper oxide (CuO). The equation of the reaction involved on heating copper is given below. `underset("Shiny brown in colour")(2Cu+O_2(G))overset("Heat")tounderset("Black in colour")(2CuO)` |
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| 8375. |
A series of compounds containing the same functional group is called……………….. |
| Answer» SOLUTION :CLASSOF ORGANIC COMPOUNDS | |
| 8376. |
A scientist was studying reactions of metals andnon-metals. He knew group 1 and 2 elementsare metals while group 17 elements are non- metals. So, he chooses different elements from group 1, group 2 and group 17. Write the formula of compound formed in the reaction between calcium and fluorine. |
| Answer» Solution :The formula of COMPOUND FORMED in the reaction , between Calcium (Ca) and FLUORINE (F) is CAF, (Calcium Fluoride). | |
| 8377. |
A scientist was studying reactions of metals andnon-metals. He knew group 1 and 2 elementsare metals while group 17 elements are non- metals. So, he chooses different elements from group 1, group 2 and group 17. Write the formula of compound formed in the reaction between lithium and bromine. |
| Answer» Solution :The formula of compound formed in the REACTIONBETWEEN lithium (LI) and BR~mine (Br) is LIBR (Lithium bromide). | |
| 8378. |
A scientist was studying reactions of metals andnon-metals. He knew group 1 and 2 elementsare metals while group 17 elements are non- metals. So, he chooses different elements from group 1, group 2 and group 17. Name the element in group 17 which forms adiatomic molecule and exists in solid state atroom temperature. |
| Answer» Solution :The element in GROUP 17 which FORMS a diatomicmolecule and exists in SOLID state at room temperature is Iodine. | |
| 8379. |
A scientist was studying reactions of metals andnon-metals. He knew group 1 and 2 elementsare metals while group 17 elements are non- metals. So, he chooses different elements from group 1, group 2 and group 17. Name the element in group 17 which belongs tothe same period as sodium. |
| Answer» Solution :The element in GROUP 17 which BELONGS to the same PERIOD as SODIUM (Na) is chlorine (CL). | |
| 8380. |
A scientist was studying reactions of metals andnon-metals. He knew group 1 and 2 elementsare metals while group 17 elements are non- metals. So, he chooses different elements from group 1, group 2 and group 17. What is the valency of magnesium? |
| Answer» SOLUTION :As Magnesium belongs to GROUP 2, its valency is 2. | |
| 8381. |
A saturated hydrocarbon reacts with chlorine in the presence of ____ |
| Answer» SOLUTION :SUNLIGHT | |
| 8382. |
A sanitary worker uses a white chemical having strong smell of chlorine gas to disinfect the water tank. (i) Identify the chemical compound write is chemical formula. (ii) Give chemical equation for its preparation. (iii) Write its two uses other than disinfection. |
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Answer» Solution :(i) Bleaching powder- `CaOCl_2` (II) `Ca(OH)_2+Cl_2 to CaOCl_2+H_2O` (III) TWO uses other than disinfection are: (a) PAPER industries (b) Chemical industries. |
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| 8383. |
A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish-orange. Which of the following would change the colour of this pH paper to greenish-blue ? |
| Answer» Solution :An antacid | |
| 8384. |
A sample of pure water, irrespective of source, contains 88.89% oxygen and 11.11% hydrogen by mass. The data supports the |
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Answer» law of conservation of mass |
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| 8385. |
A sample of air contains nitrogen and oxygen saturated with water vapour.The total pressure is 640 mm. The vapour pressure of water vapour is 40 mm and molar ratio of nitrogen and oxygen is4 : 1. Find out the partial pressures of N_(2) and O_(2). |
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Answer» Solution :TOTAL pressure, `P_(N_(2))+P_(O_(2)) + P_(H_(2)O) = 640` mm Vapour pressure of water vapour = 40 mm `:. P_(N_(2)) + P_(O_(2)) = 640 - 40 = 600` mm Mole fraction of nitrogen = 4/5 Mole fraction of oxygen = `1/5` Partialpressure of `N_(2) = " total pressure" xx X_(N_(2)) = 600 xx 4/5 = 480` mm PARTIAL pressure of `O_(2) = 600 xx 1/5 = 120` mm |
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| 8386. |
A sample of a mixtureof Na_(2)CO_(3) and NaHCO_(3) is subjected toheatingtill there is nofurther loss in weight. Assuming, that the loss in weight of thesample is 22% of theinitial weight of the mixture due to theevolution of CO_(2), find out the relative percentages of the two components in themixture. |
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Answer» Solution :(i) action of heating on the compounds `Na_(2)CO_(3) and NaHCO_(3)`. (ii) determination of the mass of `Na_(2)CO_(3) and NaHCO_(3)` from themass of `CO_(2)` produced (iii) `84%NaHCO_(3)` `16%Na_(2)CO_(3)` |
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| 8387. |
A sample of soil is mixed with water and allowed to settle. The clear supernatant solution turns the pH paper yellowish - orange. Which of the following would change the colour of this pH paper to greenish- blue? |
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Answer» Lemon juice |
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| 8388. |
A salt X when dissolved in distilled gives a clear solution which turns red litmus blue . Explain this phenomenon. |
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Answer» SOLUTION :Basic solution turn red litmus paper . The salt of a weak acid and strong base given a basic solution . So , the given salt X is the salt of a weak acid and a strong base. Example : When sodium carbonate is dissolved in water, it gets hydrolysed to some extent and forms sodium hydroxide and carbonic acid. `underset(("Basic salt"))underset("Sodium carbonate")(Na_2CO_(3)(s))+underset("water")(2H_(2)O(l))overset("Hydroysis")hArrunderset(("strong base"))underset("Sodium hydroxide")(2NaOH(aq))+underset("(weak acid)")underset("Carbonic acid")(H_(2)CO_3(aq))` Being a strong base, sodium hydroxide is fully ionised and gives a large amount of hydroxide IONS `(OH^(-))` . Carbonic acid is a weak acid which is only slightly ionised and hence , given a small amount of hydrogen ions `(H^(+))` . The `H^(+)` ions produced by carbonic acid NEUTRALISES only a small amount of `OH^(-)` ions produced by sodium hydroxide and the rest amount of `OH^(-)` ions are present in the solution. Hence , the `Na_(2)CO_(3)` solution is basic in nature . It turns red litmus blue. |
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| 8389. |
A salt, X is prepared by the complete neutralisation of Cu(OH)_(2) " with " H_(2)SO_(4). The nature of X is _______ |
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Answer» |
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| 8390. |
A salt X is formed and a gas is evolved when ethanoic acid reacts with sodium hydrogen carbonate. Name the salt X and the gas evolved. Describe an activity and draw the diagram of the apparatus to prove that the evolved gas is the one which you have named. Also, write the chemical equation of the reaction involved. |
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Answer» Solution :X is sodium ethanoate. Gas evolved is carbon dioxide. Activity: (i) Set up the apparatus as shown in the figure. (II) Take a spatula-full of sodium hydrogencarbonate in a test tube and add 2 ML of DILUTE ethanoic acid. (iii) We observe that brisk effervescence of a gas is produced in the test tube. (iv) Now pass the gas produced through freshly prepared lime WATER. It is observed that lime water turns milky. Only carbon dioxide gas can turn lime water milky. So, this activity proves that when ethanoic acid reacts with sodium hydrogencarbonate, then carbon dioxide is evolved. `CH_(3)COOH +NaHCO_(3) to CH_(3)COONa+H_(2)O+CO_(2)` |
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| 8391. |
A salt is formed between a bivalent metal cation and an oxyacid of a non-metal. The-ous acid of the non-metal has twooxygen atoms per molecule. If thesalt contains a radicalof per acidof the same non-metal, calculate the number of atoms of variouselements present in 0.5 moles of thesalt. |
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Answer» Solution :(i) identification of acidic redical and formula of salt (ii) determination of theformula ofthe 'per' acidradical (III) determination of the formula ofthesalt (IV) determination of thenumber of atoms of each CONSTITUENT ELEMENT, present in one molecule of thesalt (v) determination of thenumber of atoms of each constituent element, present in 5 moles of the salt (vi)4 N oxygen atoms N chlorine atoms |
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| 8392. |
A response that does not happen in plants due to their growth is |
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Answer» BENDING of SHOOT towards light |
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| 8393. |
A reddish-brown metal which lies below hydrogen in the activity series of metals reacts with concentrated H_(2)SO_(4)to produce4 sulphur dioxide gas. The metal is |
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Answer» ZINC |
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| 8394. |
Areddish brown metal A when exposed to moist air forms a green layer B. When A is heated at different temperature in the presence of O_(2) it forms two typws of oxide -C (black ) and D red identify A, B, C, d and wrtie the balanced equation . |
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Answer» Solution :(i) A reddish BROW metal A is copper (Cu) (ii) when oppere (A) is exposed to moistair it forms green LAYER (B) is copper carbonate `Cu+O_(2)+CO_(2)+H_(2)OrightarrowCuCO_(3).CU(OH)_(2)` Copper carbonate (B) (iii) When copper is HEATED at different temperature in the presensence of oxygen , it forms two types of OXIDES `CuO` and `Cu_(2)O` ( Cand D) `2Cu+O_(2)("below"1370K)/(Delta)2CuO` `4Cu+O_(2) ("above"1370K)/(Delta)2Cu_(2)O` 
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| 8395. |
A red litmus paper when dipped in an aqueous solution of potassium acetate turned blue. Arrange the following steps in proper sequence to explain the above observation. (1) identification of spectator ions (2) identification of free ions that caused the colour change of the litmus paper (3) identification of positive and negative radicals (4) writing the net reaction taking place (5) writing ionic equation for the reaction of positive and negative radicals with water |
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Answer» 3 5 1 4 2 (ii) writing ionic equations for the reaction of positive and negative radicals with WATER (III) identification of spectator IONS (IV) writing the net reaction taking place (v) identification of free ions that caused the colour change of litmus paper |
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| 8396. |
A red brown gas is released on heating lead nitrate. It is an example of |
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Answer» COMBINATION reaction |
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| 8397. |
A reaction takes place in two steps. The rates of the two elementary steps are given. On the basis of these, predict the rate of reaction with changes in concentration. Also the given units of rate constant are 2A_((g)) + B_(2(g)) to 2AB_((g)) to Overall reaction A + B_(2) to AB+B in the first step, r=3.2xx10^(4) mol L^(-1) s^(-1) B + A to AB, in the second step , r=1.9xx10^(6)mol L^(-1)s^(-1) |
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Answer» Solution :(i) rate-determining step of a reaction (ii) DETERMINATION of rate law on the BASIS of STOICHIOMETRY of the rate-determining step (iii) determination of change in rate of reaction with the change of CONCENTRATIONOF the REACTIONS from rate law (iv) determination of the unit of rate constant from rate law |
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| 8398. |
A reaction im which a single product is formed from two or more reactants is known as displacement reaction |
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Answer» Solution :FALSE CORRECT statement:A reaction in which a SINGLE product is formed from two or more reactants is KNOWN as combination reaction. |
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| 8399. |
A reaction between carbon and oxygen is reaction is represented by C_((s))+O_(2(g))toCO_(2(g))+Heat in which of the type (S),the above reaction can be classified? (i)Combination Reaction (ii)Combustion Reaction(iii)Decomposition Reaction (iv) Irreversible Reaction |
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Answer» I and ii It INVOLVES combusion of carbon to FORM `CO_(2)` The reaction is irreversible and we cannot reverse the reaction. |
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| 8400. |
A reaction between an acid and a base is called…… |
| Answer» SOLUTION :NEUTRALIZATION | |