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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.
| 1052. |
Small quantities of water and ether are placed on the palms of both the hands. Which will experience more cooling ? |
| Answer» SOLUTION :The palm containing ether will experience extra cooling. Actually ether is more volatile than WATER. THEREFORE, it will EVAPORATE at a faster rate than water. Since cooling is always caused during evaporation, the palm containing ether will become cooler. | |
| 1053. |
Small pieces of steel and some powdered rust are taken in two test tubes separately. What will you obseve when concentrated hydrochloric acid is poured into both the test tubes ? Justify your observation. |
| Answer» SOLUTION :Steel is an alloy, i.e., a mixture in which iron is the major component and it retains its property in steel. Hence, PIECES of stell will liberate hydrogen and effervescence will be observed. However, rust being a compound of iron does not exhibit the chemical property of iron. Rust dissolves in hydrochloric and due to the formatio ferric CHLORIDE and no effervescence will be observedin that test tube. | |
| 1054. |
Since metal carbonate and metal bicarbonate are basic they reactwith acids to give salt and water with the liberation of ...... a. NO_(2) b. SO_(2) C. CO_(2) |
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| 1055. |
Silicon is a metalloid |
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| 1056. |
Silicon forms a compound with chlorine in which 5.6 g of silicon is combined with 21.3 g of chlorine. Calculate the empirical formula of the compound (Atomic mass : Si = 28 , Cl = 35.5) |
Answer» Solution : The simplest whole number RATIOS of different ELEMENTS are: SI :Cl: :1 :3 The formula of the compound =`SiCl_(3)` |
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| 1057. |
Silica acts a ________________in the process of extraction of iron from its oxides. |
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| 1059. |
Show the relation among mole, avogadro number and mass. |
Answer» SOLUTION :
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| 1060. |
Show by a diagram the distribution of electrons in sodium ion. |
Answer» SOLUTION :
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| 1061. |
Shaving cream and pumice are foams. What is the difference in their dispersing mediums? |
| Answer» SOLUTION :The dispersing MEDIUM of SHAVING cream is liquid while that of pumice is SOLID. | |
| 1062. |
Shalini, the school teacher, travels in school bus with other students. The school bus is fitted with CNG cylinder. She told the driver of the bus to check at times for any leakage in CNG. She told the driver tobe more careful especially during summer. 1. What is CNG? |
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Answer» Solution :1. The compressed Natural GAS used as fuel is called CNG. 2. The gas expands when heated. During summer, it is hot and the CNG in the cyliner will EXPAND. If there is any leakage, the gas would come out of the cylinder and it AMY cause FIRE in the bus. 3. The values depicted by Shaline are a. concerned citizen and B. morally responsible behaviour. |
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| 1063. |
Shantabai lives in a village. She does not have a refrigerator or AC in her home. During summer she keeps wet cloth around the earthen pot. She keeps vegetables. Wrapped in cloth and sprimkles water over it. 1.Why did Shantabai keep wet cloth around the earthen pot? 2. How can she keep her home cool during summer? 3 What values of Shantabai are depicted here? |
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Answer» Solution :1. The water in the wet cloth evaporates causing cooling EFFECT. Thereby the water in the earthen pots remains cool. 2. She sprinkles water in the courtyard of her home. This causes a cooling effect. 3 Shantabai.s values like practicle outlook, caring attitude for the family are DEPICTED here. |
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| 1065. |
The valency of nitrogen in nitrogen dioxide (NO_2)is |
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Answer» 1 |
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| 1066. |
Name the following:An alkaline earth metal in period 3 of the periodic table. |
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Answer» Ba |
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| 1067. |
Select the correct answer from the following: A salt which leaves yellow residue on heating : |
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Answer» `CU(NO_(3))_(2)` |
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| 1068. |
Seema visited a Natural Gas Compressing Unit and found that the gas can be liquefied under specific conditions of temperature and pressure . While sharing her experience with friends she got confused . Help her to identify the correct set of conditions. |
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Answer» LOW temperature, low PRESSURE |
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| 1069. |
The 'sea-water' can be classified as a homogeneous as well as heterogeneous mixture. Comment. |
| Answer» Solution :The sample of sea water from mid stream is transparent and has certain SALTS dissolved in water. It is THEREFORE, homogeneous., However, the sample collected from NEAR the seashore contains mud and MANY suspended particles. It is therefore, heterogeneous in NATURE. | |
| 1070. |
Sea breeze and land breeze occur in the coastal areas. |
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| 1071. |
Scientist ...... discovered subatomic particle which had no charge. (J. J. Thomson, J. Chadwick, E. Goldstein ) |
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| 1072. |
Scattering of light by milk is called electrophoretic effect . Is the statement correct ? |
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| 1073. |
Same fraction of petroleum refining are used as dry cleaning liquids and some fractions aer used as lubricationg oils, What are the requisite characteristics of those fractions ? |
| Answer» Solution :The EASILY vapourisable fractions obtained from petroleum are used as dry cleaning liquids due to their volatile nature .The fractions which have higher boiling pints are used as lubricanting oils due to their volatile nature.The fractions which have higher boiling points are used as lubricating oils due to their HIGH THERMAL RESISTANCE . | |
| 1074. |
Salt can be recovered from its solution by evaporation. Suggest some other technique for the same. |
| Answer» SOLUTION :SALT can be RECOVERED from its solution by CRYSTALLISATION. | |
| 1075. |
Salt can be recovered from its solution by evaporation. Suggest some other technique for the same? |
| Answer» SOLUTION :Crystallisation technique can also be used. For example, both these can be used to SEPARATE SALTS like sodium CHLORIDE (common salt) and potasium NITRATE (nitre) from their aqueous solution. | |
| 1076. |
Rutherford's alpha-particle scattering experiment showed that (i) electrons have negative charge. (ii) the mass and positive charge of the atom is concentrated in the nucleus. (iii) neutron exists in the nucleus. (iv) most of the space in atom is empty. Which of the above statements are correct ? |
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Answer» I and III |
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| 1077. |
Rutherford's alpha - particle scattering experiment was responsible for the discovery of |
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Answer» ATOMIC nucleus |
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| 1078. |
Rutherford selected foll of . metal in scattering of alpha-particles experiment. |
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| 1079. |
Rutherford concluded from hisalpha-ray scattering experiment that there exists a heavy and dense body at the centre of the nucleus . |
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| 1080. |
Ruterford's alpha-particle scattering experiment eventually led to the conclusion that |
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Answer» mass and energy are RELATED |
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| 1081. |
Rusting of iron is a ____ reaction. |
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| 1083. |
Rusting of an article made up of iron is called |
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Answer» CORROSION and it is a physical as WELL as CHEMICAL change |
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| 1084. |
Rusted iron is washed with phosphoric acid before soldering Justify. |
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Answer» Solution :(i) comparision of ignition TEMPERATURE (II) surfaces of metals to be soldered (III) reactivity of phosphoric acid with rust, IMPURITIES (iv) produces formed and NATURE of products |
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| 1085. |
Rub aglassrodwitha silkclothand bringtherodnearan inflatedballoon . Whathappens ? |
| Answer» SOLUTION :the glassrodattractsaninflatedballoon . | |
| 1086. |
Roshni is a student of class IX in a school in Delhi. One day Roshni's mother, Mrs. Deepa, was complaining that the woollen and silk clothes which she had stored steel trunks had been partially eaten up and damaged by some tiny insects. Mrs. Deepa had to spend a lot of money to get these damaged clothes repaired. When Roshni heard her mother complaining, she asked her to place some small, white balls of a particular material inside the folds of the woollen and silk clothes before storing them again in trunks, and closing the lids of trunks properly. Mrs. Deepa did the same. When Mrs. Deepa opened the trunks again after about six months to take out a silk saree for a marriage function, she found that the stored clothes had remained safe, they had not been damaged this time. At the same time, she noticed that the small white balls placed inside the folds of clothes had become much smaller in size. Mrs. Deepa asked Roshni why the white balls had become much smaller in size on keeping. Roshni explained everything to her mother. Roshni also told her mother that one day a,, the white balls placed for protecting stored woolen and silk clothes would disappear completely without leaving behind any residue and then new balls will have to be placed for further protection of stored clothes. (a) What is the usual name of the tiny insects which eat up and damage stored woolen and silk clothes in Roshni's home ? (b) What is the material of small white balls placed in stored woolen and silk clothes by Mrs. Deepa ? (c) How do the small white balls placed inside the folds of stored clothes work to prevent damage to stored clothes ? (d) Why do small white balls kept within the folds of stored woolen and silk clothes become smaller and smaller with time and ultimately disappear completely one day ? What is the special name of the process which makes the white balls become smaller or disappear completely without leaving behind any residue ? (e) Name one other material whose balls can also be used for the protection of stored woolwn and silk clothes ? (f) What values are displayed by Roshni in this episode ? |
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Answer» Solution :(a) Moths (or Clothes moths) (b) Naphthalene (c) Naphthalene is an insecticide. The solid naphthalene balls give off toxic vapours (or poisonous vapours) slowly. These toxic naphthalene vapours get trapped within the layers of STORED clothes and kill the moths that damage the clothes (d) Naphthalene is a solid organic compound which undergoes sublimation and gets converted into vapours (or GAS) DIRECTLY. So, when naphthalene balls are PLACED in stored clothes, they take heat from the surroundings and sublime (vaporise) slowly. Due to gradual sublimation (conversion into vapours) of naphthalene balls, their size goes on decreasing. And when these naphthalene balls sublime completely, they just disappear. So, the special name of this process is sublimation (e) Camphor (f) The various values displayed by Roshni in this episode are (i) Knowledge that naphthalene is an insecticide and undergoes sublimation (ii) Application of knowledgein SOLVING everyday problems, and (iii) Desire to help her mother (by preventing damage to stored clothes). |
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| 1087. |
Rohit and Arun are two friends both of whom study in class IX in different schools. Earlier Rohit's mother used to purchase ordinary common salt for cooking food. But since the time Rohit had studied the benefits of using iodised common salt, the had made his mother purchase and use only iodised salt for cooking food. One day, while working in the kitchen, Rohit's mother mixed some ammonium chloride in iodised salt container by mistake. Rohit and Arun had recently studied the various method of separation of mixtures in the class. They started discussing the components and the method of separation of the mixture made by Rohit's mother unknowingly. Arun said that the mixture obtained by mixing ammonium chloride with iodised salt actually contains ammonium chloride, iodine and salt in it, so they had to use more than one method to separate this mixture into its components. Rohit, however, did not agree with Arun. He explained his point of view to Arun (a) What are the benefits of using iodised salt ? (b) What can you say about Arun's statement that the mixture obtained by mixing ammonium chloride and iodised salt contains ammonium chloride, iodine and salt ? (c) Name and define the process which can be used for the separation of mixture containing ammonium chloride and iodised salt (d) Describe briefly, how a mixture of ammonium chloride and iodised salt can be separated. (e)What values are displyed by Rohit in this episode ? |
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Answer» Solution :(a) The benefits of using iodised salt are as follows : (i) Iodised salt provides iodine to thyroid gland for making thyroxine hormone which regulates metabolism, growth and development of the body. It also PREVENTS 'goitre' disease (ii) Iodised salt provides iodine which improves the functions of brain such as memory, concentration and the ability to lean (b) Arjun's statement is not correct. This is because iodised salt does not contain free iodine element `(I_(2))`. Iodised salt usually contains iodine in the form of its salt, potassium iodide (KI). Moreover, iodised salt contains minute quantity of potassium iodide (which is only about 0.01 percent of salt) (c) The MIXTURE of ammonium chloride and iodised salt can be separated by the PROCESS of sublimation. The changing of a solid directly into vapours on heating, and of vapours into solid on cooling is called sublimation (d) The mixture of ammonium chloride and iodised salt is heated in a CHINA dish convered with an inverted funnel having a loose cotton plug at the TOP end. Ammonium chloride sublimes on heating and collects as a sublimate on the cold, inner walls of the inverted funnel. Iodised salt does not sublime, so it is left behind in the china dish (e) The values displayed by Rohit in this episode are (i) Awareness of the composition of iodised salt (that it is mostly common salt with minute quantity of potassium iodide but no free iodine) (ii) Knowledge that ammonium chloride sublimes but common salt and potassium iodide present in iodised salt do not sublime (iii) Application of knowledge in solving everyday problems, and (iv) Concern for the health of his family (in enforcing use of iodised salt). |
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| 1088. |
Rima took fine chalk powder egg albumin starch powder and alum powder in four test tubes A,B,C, and Drespectively .After adding water to all the fourtest tubes, identify the test tubes as true solution suspension and colloid. |
| Answer» Solution :TRUE solution is formedin test tube D. Test tube A contains SUSPENSION while colloidal SOLUTOINS are FORMED in test tubes B and C | |
| 1089. |
Rhombic sulphur is the most stable form of sulphur at noramal temperature. |
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| 1090. |
Relation between electrochemical equivalent (e) and equivalent mass (E) is given by |
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Answer» `E = (e)/(96500)` |
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| 1091. |
Reactions involved in the smelting of iron in the blast furnace are given below. Arrange them in the correct sequence. (1) CaCO_3to CaO+CO_2+43kcal (2) CaO+SiO_2toCasiO_3 (3)C+O_2toCO_2+97kcal (4) CO_2+CtoCO-39kcal (5) FeO //Fe_2O_3+COtoFe+CO_2 |
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Answer» 34125 (II) `CO_2+Cto2CO-39 KCAL` (III) `CaCO_3to CaO+CO_2+43 kcal` (IV) `CaO+SiO_2 to CaSiO_3` (V) `FeO//Fe_2O_3+COtoFe+CO_2` |
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| 1092. |
Reaction taking place in lower region of blast furnace is associated with __________________ of energy. |
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| 1093. |
Reaction : FeCl_3+H_2StoFeCl_2+HCI=S in the above reaction |
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Answer» `H_2S` is the REDUCING AGENT |
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| 1094. |
Reactants A and B can react to give two different products C and D in two different reactions. The two reactions take place in two different mechanisms and D is found to be more energetically stable than C. But product C was found in larger amounts. How do you account for this ? |
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Answer» Solution :(i) FACTORS affecting the rate of reaction and the AMOUNT of product formed (ii) comparison of ACTIVATION ENERGY of both mechanisms (III) effect of activation energy on the amount of product formed |
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| 1096. |
Ram went to a grocer and asked for 2 moles of washing soda(Na_(2)CO_(3)*10H_(2)O). Calculate the amount ofwashing soda which the grocer should weigh for him . |
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| 1097. |
Ramnik is a student of class 9. One day he was studying a chapter of chemistry in the class alongwith other students. The teacher, Mr. Bhagi, told the students that the scientists James Chadwick J.J. Thomson and E. Goldstein had discovered three subatomic particles P, Q and R, respectively. He gave the characteristics of all these particles, their locations and arrangements in the atom. Mr. Bhagi also described the contributions of scientists Ernest Rutherford and Neils Bohr in this regard. After completing the discussion on this chapter, Mr. Bhagi asked Ramnik to answer the following question : (a) What is the name of particle P ? What is the nature of charge on it ? State its location in tha atom (b) What is the name of particle Q ? What is the nature of charge on it ? State its location in the atom (c) What is the name of particle R ? What is the nature of charge on it ? State its location in the atom (d) (i) Which of the particles P,Q and R is not present in an ordinary hydrogen atom (ii) Which of the particles P,Q and R is not present in an alpha particle ? (e) What is the total number of P and R particles present in one atom of an element known as ? . (f) The number of particles Q in one neutral atom of an element is nineteen. How are these particles arranged in various energy levels in the atoms ? (g) What values are displayed by Ramnik in this episode ? |
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Answer» Solution :(a) James Chadwick discovered the subatomic particle called 'neutron'. So, the particle P is neutron. Neutron has no charge, it is electrocally neutral. Neutron is located inside the nucleus of an atom (b) J.J. Thomson discovered the subatomic particle called electron. So, the particle Q is electron. Electron has negative charge. The relative charge of an electron is, -1 (MINUS one). Electron is located outside the nucleus in an atom (c) E. Goldstein discovered the subatomic particle called 'PROTON'. So, the particle R is proton. Proton has positive charge. The relative charge of a proton is +1 (PLUS one). Proton occurs inside the nucleus of an atom. (d) Particle P (neutron) is not present in an ORDINARY hydrogen atom (ii) Particle Q (electron) is not present in an alpha particle. (e) The total number of particles P (neutrons) and R (protons) in one atom of an element is called its mass number (f) The number of particle Q (or electrons) in one neutral atom of the element is 19. These 19 electrons can be arranged in four energy levels or shells as `UNDERSET("2,8,8,1")("KLMN")` (g) The various values displayed by Ramnik in this episode are (i) Knowledge of the structure of atom, and (ii) Ability to use this knowledge in solving problems. |
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| 1098. |
Rama tested the solubility of four substances at different temperatures and found in grams of each substance dissolved in 100 g of water to form a saturated solution.{:(,"Substance dissolved",,"Temperature (K)",),(,"(in grams)","293 K","313 K","333 K"),(1.,"Ammonium chloride","37 g","41 g","55 g"),(2.,"Potassium chloride","35 g","40 g","46 g"),(3.,"Sodium chloride","36 g","36 g","37 g"),(4.,"Potassium nitrate","32 g","62 g","106 g"):}(i) Which substance is least soluble at 293 K. (ii) Which substance shows maximum change in its solubility when the temperture is raised from 293 K to 313 K ? (iii) Find the amount of ammonium chloride that will separate out when 55 g of its solution at 333 K is cooled to 293 K. (iv) What is the effect of temperature on the solubility of a salt ? (v) What mass of sodium chloride would be needed to make a saturated solution in 10 g of water at 293 K ? |
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Answer» Solution :(i) Potassium nitrate is least soluble in water at 293 K. (ii) Potassium nitrate shows maximum change in its solubility which is 30 g (62-32) per 100 g of water. (iii) From the available INFORMATION, 55 g of ammonium chloride solution UPON cooling from 333 K to 293 K SEPARATES salt = (55 - 37) = 18 g. (iv) From the available information, it is clear that the solubility of salt in water increases with the rise in temperature At 293 K, in a saturated solution, 100 g of water has SODIUM chloride = 36 g 10 g of water has sodium chloride = 3.6 g |
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| 1099. |
Rajesh uses car to go to his office. He uses unleaded petrol and have his car always checked for pollution. Whenever possible he uses public transport. (1) What pollutant is given out by car ? (2) What is smog ? (3) What values of Rajesh are reflected here ? |
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Answer» Solution :(1) Automobile exhaust is the pollutant GIVEN out by car. (2) Fog intesified by SMOKE is called SMOG. It is dangerous for health. (3) Rajesh is aware of environmental pollution and a CONCERNED citizen. |
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| 1100. |
Raghvan is a student of class 9 in a Chennai school. His teacher, Mr. Murthy, had just finished a lecture on various types of changes which take place even in the same substance under different experimental conditions. Mr. Murthy gave a beaker full of a common liquid to Raghav. A drop of this liquid can turn anhydrous copper sulphate blue. Mr, Murthy than asked Raghav to perform two different experiements starting with the given liquid which lead to the formation of gas/gases under different experimental conditions. He also asked Raghavan to classify these changes under different types of changes. Raghvan first arranged a distillation apparatus. He took some of the given liquid in the distillation flask and started heating it with a burner. After some time, a gas started forming and going into the condenser. The condenser cooled the gas and re-converted it into the original liquid. Raghvan then arranged an apparatus to pass electric current into the given liquid. He took the given liquid in the appropriate apparatus, acidified it by adding a little of sulphuric acid, and then passed electric current from a battery for a considerable time. He collected two gases in the two water-filled test-tubes inverted over the twoelectrodes of the apparatus. When the mixed these two gases and ignited this mixture very,very carefully (with the help of his teacher), he heard a little explosion and saw the drops of original liquid being formed. Raghvan both the experiments and the conclusions obtained to his teacher. Mr. Murthy was very happly (a) What do you think was the liquid give to Raghvan by Mr. Murthy ? (b) Which gas is formed when heat energy is applied to the liquid in the distillation flask ? What type of change occurs in this case ? (c) Which two gases are formed when electric energy is applied to the acidified liquid in the appropriate appartus ? What type of change occurs in this case ? (d) How does the above change (which occurs on passing electric current through acidified liquid) differ from the change which takes place when a piece of paper is burnt ? (e) What values are displayed by Raghvan in this episode ? |
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Answer» SOLUTION :(a) The liquid which turns anhydrous copper sulphate blue is water. So, the liquid given to Raghvan by Mr. Murthy was water (b) When heat ENERGY is APPLIED to water in the distillation flask, then water boils to form 'steam' as gas. The change which occurs in converting water into steam is a physical change (c) When electric energy is applied to acidified water in the appropriate apparatus, then two gases, hydrogen and oxygen, are formed. The change which occurs in converting water into hydrogen and oxygen is a CHEMICAL change (d) The chemical changes are permanent changes which usually cannot be reversed. But the chemical change of decomposing water into hydrogen and oxygen gases by passing electricity is an exception because it can be fairly easily reversed (by burning hydrogen in oxygen to form water again). On the other hand, the burning of paper to form carbon dioxide, water vapour, SMOKE and ash is a chemical change which cannot be reversed at all. (e) The values displayed by Raghvan in this episode are (i) Knowledge of physical changes and chemical changes (ii) Application knowledge in solving problems, and (iii) Boldness (to accept challenge). |
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