InterviewSolution
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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.
| 251. |
What is the 4 R principle? |
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| 253. |
What is nylon? |
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| 254. |
Two samples each of substance A and B are kept in an open container and air tight container . Sample A in first container became sticky and in second container remained as such. Sample B in both the containers remained without any change. Comment on the above observation. |
| Answer» Solution :SUBSTANCE A in open container becomes sticky and that means it is a deliquescent substance and absorbs sufficient MOISTURE in an open container . In an AIR tight container, it absorbs little moisture but again loses some moisture for maintaining equilbrim vapour pressure. THEREFORE, it does not become sticky EVEN in opencontainer. The fact that it remained without any change in open container indicated that it is neither efflorescent nor deliquescent . It may be a hygroscopic salt or may not absorb moisture at all. | |
| 255. |
The thermal expansion of solids is the least among solids, liquids and gases. Justify. |
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Answer» Solution :(i) Effect of external supply of heat energy on molecular ARRANGEMENT of a substance. (II) Comparison of forces acting between the molecules in solids, liquids and GASES. (III)The effect of heat on the molecular arrangement of a substance. (iv) Comparison of the efect in solid, LIQUID and gases. |
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| 256. |
Can you list some inflammable substances? |
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| 257. |
What are fossil fuels ? |
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| 258. |
What is a displacement reaction? |
| Answer» SOLUTION :More actiw METAL displaces LESS ACTIVE metal from its COMPOUND. | |
| 259. |
What is the difference between photochemical and thermochemical reactions? |
| Answer» SOLUTION :REACTION in the PRESENCE of LIGHT and HEAT | |
| 260. |
What is chemical equation? W rite the steps involved in writing a chernical equation |
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Answer» Solution :(i) Representation of a CHEMICAL change. (II) LEFT hand side reac TANTS, right hand side PRODUCTS. |
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| 261. |
Why are dense white fumes formed when hydrogen chloride is dissolved in moist air |
| Answer» SOLUTION :DUE to FORMATION of HYDROCHLORIC ACID | |
| 262. |
Which of the following can be considered as spontaneous combustion gt |
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Answer» BURNING of LPG |
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| 263. |
Which of the following metal reacts vigorously with cold water? |
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Answer» ZINC |
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| 264. |
Two non metallic gaseous elements react in 1 : 3 ratio to give another gasX . A mixture of X and oxygen is taken in a jar and a burning match stick is introduced into it. Another sample of the same mixture containing large excess of O_2, is passed over heated platinumThe mixture of gaseous products is dissolved in water to giveY and Z which are colourless. Zon long standing turnst o yellow, Identify X,Y and Z by giving reasons wherever necessary.Also identify the exothermic reaction in the above sequence. |
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Answer» Solution :(i) Identification of the acid which turns to yellow on LONG standing. (II) Identification of X. (iii) Products OBTAINED in the two jars. (iv) COMPARISON ofreactivity of products in the respective jars with water. (v) Products obtained. (vi) Identification of Y and Z. |
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| 265. |
What happens to the cathode rays under a strong magnetic field or an electric field ? What isconclusion made from this ? |
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Answer» SOLUTION :Electric field-move towards POSITIVE PLATE,negatively charged. Magnetic field-deflect PERPENDICULAR to the APPLIED magnetic field. |
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| 266. |
What is 'Marble cancer'? |
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| 267. |
What are air pollutants? |
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| 268. |
Where can metals be used? |
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| 270. |
What are the major components of air? Among these, which is the active component and which is the inactive component? |
| Answer» SOLUTION :OXYGEN, NITROGEN, CARBON DIOXIDE oxygen, Nitrogen. | |
| 271. |
Where and when was the world'sfirst oil well drilled? |
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| 272. |
Which of the following formula representation is NOT correct? |
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Answer» `H_(2)O` |
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| 273. |
Thermoplastics can be moulded again and again where as thermosettings cannot bem oulded. Give reason |
| Answer» Solution :Thermoplastic plastics consist of long CHAINS which can be moulded again and again whereas in case of THERMOSETTING plastics consist oflong chain and are cross LINKED with each other. LINKAGE prevents the DISPLACEMENT ofindividual chains on being heated and thus thermosetting polymers do not change once they have set | |
| 274. |
What is fuel? |
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| 276. |
'Though oxygen is the supporter of life on earth, the presence of nitrogen in the atmosphere also contributes equally to the life processes on earth''. Justify the statement. |
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Answer» SOLUTION :(i) Consequences of BREATHING AIR with 100% oxygen. (ii) Effect on body on breathing 100% `O_(2)` (iii) Components of the air we breathe in (under normal conditions). (IV) Role of nitrogen. |
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| 277. |
Write the products obtained in following reactions? {:((i)Na_(2)O +H_(2)O to ),((ii) CO_(2)+H_(2)O to ),((iii) CO+H_(2)O to ),((iv) SO_(2)+H_(2)O to ):}}"Nature of reactants " |
| Answer» SOLUTION :NATURE of the REACTANTS. | |
| 278. |
Which of the following is a suspension? |
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Answer» milk |
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| 279. |
Theory used to explain the arrangement and movement of molecules in matter. |
| Answer» SOLUTION :KINECTIC ENERGY of MATTER | |
| 280. |
Two samples of sulphur are heated separately startirig at 60^@C. One sample is found to melt at 114^@C and the other one melts at 119^@C. How do you account for this |
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Answer» Solution :(i) Allbtropes of SULPHUR. (ii) STABILITY of allotropes at different temperatures. (iii) Comparison of melting points of different allotropes. (iv) Pattern of HEATING to be employed. (V) Effect of pattern of heating on the allotropic TRANSFORMATION. |
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| 281. |
Write two effects of global warming. |
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| 282. |
What are the change that take place in lead nitrate solution by passing impure hydrogen through it ? |
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Answer» Solution :(i) Impurity PRESENT in HYDROGEN GAS. (ii) Reactivity of lead NITRATE with the impurity present in hydrogen. |
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| 283. |
When 58 g of Mg(OH)_2 reacts with 98 g of H_2SO_4, it gives 36 g of H_2O and __________ of MgSO_4. |
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| 285. |
Who suggested that an atom is a spherical cloud of positive charges in which lectrons were spread out? |
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Answer» Rutherford |
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| 286. |
Which mixture of fabrics are used in polycot, polywool and terrycot? |
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| 287. |
The substances which contaminate air are called |
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Answer» AIR pollutants |
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| 290. |
When lime water is exposed to air for a long time, very thinwhite coating is found floating on the surface. Give reasons. |
| Answer» Solution :Air contains a low percentage of `CO_(2)`. Though `CO_(2)` turns LIME water MILKY, since the amount of `CO_(2)` is less in the atmospheic air, it does not turn lime water milky. Only over a LONG period of exposure, a thin white film of `CaCO_(3)` is formed due to the minor amounts of `CO_(2)` in the atmospheric air. | |
| 291. |
Which of the following is a heterogeneous mixture? |
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Answer» milk |
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| 292. |
Why are soaps ineffective during usage With hard water which contains soluble salts of calcium and magnesium? |
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Answer» SOLUTION :(i)Composition of soap (ii) Reason for hardness of WATER (iii) Reaction between components of soap and salts IMPARTING hardness to water (iv) The NATURE of the PRODUCTS formed Effect of the products on lather formation |
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| 293. |
Which of the following elements has only one valency? |
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Answer» Phosphorous |
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| 294. |
Which of the following is not polyatomic ? |
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Answer» NITROGEN |
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| 295. |
What is the principle involved in the following methods of separation of mixtures ? (i) Fractional crystallization (ii) Magnetic separation (iii) Gravity method (iv) Separating funnel method (v) Distillation (vi)Fractional distillation (vii) Preferential liquifaction (viii) Chromatography (ix) Fractionalevaporation |
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Answer» Solution :(i) Solubility of solids in a given solvent (ii) Magnetic NATURE of one component (iii) Density variations w.r.t. a given solvent (iv) Immiscible liquids (v) Soluble SOLID in a given liquid (vi) Difference in BP (vii) ABILITY of one of component of gas to liquify under high pressure (viii) Adsorption of components of a mixture (IX) Difference in BP of gases. |
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| 296. |
Which of the following distinguishes respiration form combustion? |
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Answer» Requirement of oxygen. |
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| 297. |
What is biodegradable substance? |
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| 298. |
What are the changes observed when moist sugar is treated with anhydrous calciurn chloride and concentrated H_2SO_4 respectively? |
| Answer» SOLUTION :When MOIST suger is TREATED with anhydrus `CaCl_2`, it removes the moisture from the moist sugar due to its deliquuesent nature. The chemical composition of suger does not change in this process. Hence it is a physical change. When sugar reacts with CONCENTRATED `H_2SO_4`, it is converted to black residue called sugar charcoal. Concentrated `H_2DO_4` due to its dehydrating nature removes the hydrogen and oxygen PRESENT in the compound as water and the chemical composition of sugar changes. Hence it is a chemical change. | |
| 299. |
Which of the following particles is largely responsilbe for the chemical behaviour of elements ? |
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Answer» Proton |
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| 300. |
The transparency of glass is attributed to which of the following properties of glass? |
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Answer» High viscosity |
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