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.
| 2551. |
Choose the correct statement from the following : |
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Answer» CONVERSION of solid into vapours without passing through the liquid STATE is called vapourisation. |
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| 2552. |
Choose the correct answer from the choices given below. The property which is characteristics of an Ionic compound is that a. it often exists as gas at room temperature b. it is hard and brittle e. it undergoes molecular reactions d. It has low melting point |
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| 2553. |
Chloromethane has a certain value of dipole moment even throught the dipole moment value of methane is zero.justigy. |
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Answer» Solution :(I) The nature of bonds in `CH_3CL` and `CH_4` (i) nature of the CONSTITUENT ATOMS persent in the RESPECTIVE molecules (iii) reason for dipole MOMENT of a molecule |
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| 2554. |
Chlorine Y and iodine form a Dobereineer 's triad indetify the atomic wight of y |
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Answer» Solution :Triad of CHLORINE y and iodin ATOMIC WIGHT 35.5-127 Mean atomic WT =`(35.5+127)/(2)rarr81.25` `therefore` atomic WEIGHT of y =81.25 |
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| 2555. |
Chlorinated hydrocarbons are used as ………………….. |
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Answer» FERTILIZERS |
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| 2556. |
Chemically inert elements have …………… outermost shells. |
| Answer» SOLUTION :COMPLETELY FILLED | |
| 2557. |
Change in the number of neutrons in an atom changes it to ………… . |
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Answer» an ion |
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| 2558. |
Certain amount of washing soda crystals are exposed to atmosphere, a loss in weight was noticed. How can you account for this ? |
| Answer» Solution :WASHING SODA `(Na_(2)CO_(3)*10H_(2)O)` when exposed to air, even at ORDINARY TEMPERATURE, loses its water of crystallisation (EFFLORESCENT salt) and so anhydrous salt is left. | |
| 2559. |
Celsius scale is a scale of temperature in which zero represent the boiling point of water |
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| 2561. |
Catalyst ___ the activation energy in case of decomposition of HI. |
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| 2562. |
Castrol oil and water can be separated from its mixture by ______ . |
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| 2563. |
Carbon forms large number of organic compounds due to ________. |
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Answer» Allotropy |
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| 2564. |
Carbon do not form ionic compounds. Why? |
| Answer» Solution :CARBON shares ELECTRONS only through covalent BONDING, HENCE it does not form ionic compounds. | |
| 2565. |
Carbon dioxide was taken in an enclosed cylinder and compressed by applying pressure (a) Which state of matter will we obtain after completion of the process ? (b) Name and define this process. (c ) What is the common name of the product obtained in the above process ? |
| Answer» SOLUTION :(a) Liquid state of matter will be obtained. (b) The process is known as liquefication. It is the change of state from gas to the liquid by increasing PRESSURE or DECREASING TEMPERATURE. (c ) It is known as liquid `CO_(2)`. | |
| 2566. |
Carbon dioxide and water vapour present in air moderates the temperature of the earth. Explain. |
| Answer» Solution :Air plays a very important role in keeping the temperature of the earth within a certain range. This happens as a result of a phenomenon KNOWN as the greenhouse effect. The `CO_2` and water VAPOUR of air are transfparent to the visible radiation of the SUN that warms the earth's surface during day time. The radiated IR radiation by earth is trapped by water vapour and `CO_2` which maintains be temperature even during night time. The HEAT is trapped which keeps the earth warm even during the night. would have been abnormallly cold and life would not have existed on earth. | |
| 2567. |
Canal rays possess ........ electrical charge.(postve, negative, neutral) |
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| 2568. |
Can you separate a mixture of alcohol and water by using a separating funnel ? if not. Why? Explain how to separate them. |
| Answer» Solution :The mixture of alcohol and water cannot be SEPARATED USING a separating funnel, because they are MISCIBLE. The boiling POINTS of alcohol and water are different. So using distillation method the COMPONENT of the mixture can be separated. | |
| 2569. |
Can you find out how ionization energy changes as we move from top to bottom in a group? |
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| 2570. |
Can we separate a mixture of alcohol and water by the use of a separating funnel ? If not, suggest an alternate method. |
| Answer» Solution :No, the mixture of ALCOHOL and WATER cannot be separated by the use of separating funnel because the TWO are completely miscible with each other. The SEPARATION can be done by fractional distillation. | |
| 2571. |
Can we call the vapour of an alcohol a gas ? |
| Answer» SOLUTION :No, because the MELTING POINT of alcohol is lower than the room temperatureat 1 atmospheric PRESSURE . | |
| 2572. |
Can we call ozone an air-pollutant ? |
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| 2573. |
Can water be made to boil in a paper cup without the paper being burnt ? Explain. |
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Answer» SOLUTION :(i) CONDITION REQUIRED for buring. (II) utilisation of heatenergysupplied . |
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| 2574. |
Can water be boiled below 100^(@) C temperature ? If yes, give a reason. |
| Answer» Solution :Yes, WATER can be boiled below its BOILING POINT as the boiling point as the boiling point of the water decreases with DECREASE in PRESSURE. | |
| 2575. |
Can the process of photosynthesis occur if plants and trees are kept out of contact with sunlight ? |
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| 2576. |
Can sulphur present in ferrous sulphide dissolve in carbon disulphide ? |
| Answer» Solution :No, because in ferrous sulphide , sulphur does not retain its INDIVIDUAL PROPERTIES . | |
| 2577. |
Can phase transition be used to test the purity of gold ? |
| Answer» Solution :YES, the melting point of PURE solid is always constant. The PURITY of gold can be MEASURED with the help of its melting point. However, if the gold is not pure then it does not have a sharp melting point, because the PRESENCE of impurities reducesthe melting point of the pure gold. | |
| 2578. |
Can kerosine be used as a substitute forpetrol in autominiles ? Give reasons in supoport of your answer. |
| Answer» Solution :No kerosene cannot be used as a subtitute for petrol as an automoblie fur .Pasoline has lower iginition temperature and the hydrocarbons have corbon chain length raging from `C_5 - C_10` Kerosene has higher igition tempreratue kerosene has not be ignited by SPARK plug .Because of LONGER carbon chain it PRODUCE very high knocking which MAKES irt unsuitable for as an AUTOMOBILE fuel | |
| 2580. |
Out of atoms and molecules, which can exist independently? |
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| 2581. |
Camphor can be purified by the process of ___________. |
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| 2583. |
Calculate the volume in litres of 20 g of hydrogen gas at STP . |
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Answer» Solution :NUMBER of moles of hydrogen = `("mass of hydrogen")/("MOLECULAR mass of hydrogen in grams") = (20 g)/(2G) = 10` . `therefore` volume of hydrogen = number of moles `xx` STANDARD molecular volume `= 10 xx 22.4 = 224` litres . |
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| 2584. |
Calculate the total number of ions in 0.585 g of sodium chloride . |
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Answer» Solution :Gram formula mass of NaCl = 23 + `35*5 = 58*5` g `58.5` g of NaCl haveions = `2 XX N_(A)` 58.5 g of NaCl have ions = `2 xx N_(A) = (0.585)/(58*5) = 0*02 xx N_(A)` `=0*02 xx 6*022 xx 10^(23)` `= 1*20 xx 10^(22)` ions |
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| 2585. |
Calculate the specific charges (e/m) of the following particles and then arrange the particles in the asceding order of their specific charges. (a) Electron (b) Proton (c) alpha-particle. |
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Answer» Solution :Specific charge of an electron `=(1.6xx10^-19)/(9.1xx10^-31) " COULOMB//kg"` `=0.176xx10^12=17.6xx10^10 " coulomb /kg"` Specific charge of a proton `=(1.6xx10^(-19))/(1.67xx10^(-27))"coulomb /kg" = 0.96xx10^8 "coulomb/kg"` Specific charge of `alpha`-particle `=(2xx1.6xx10^(-19))/(2XX10^(-27)(1.67+1.72))=(1-6xx10^8)/(3.39)=0.472xx10^8 "coulomb/kg"` Hence, ASCENDING order of specific charges of electron, proton and `alpha`-particles is `alpha-"particle" lt "proton" lt "electron"`. |
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| 2586. |
Urea is a very important nitrogenous fertiliser. Its formula is CON_(2)H_(4). Calculate the percentage of nitrogen in urea. (C = 12, O = 16, N = 14 and H = 1) |
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Answer» Solution :`CO(NH_(2))_(2)` Molecular mass = `12+16+2(14+2)=60` PERCENTAGE of NITROGEN = `("Mass of nitrogen in the compound")/("Molecular mass")XX100` = `28/60xx100=46.67%` |
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| 2587. |
Calculate the percentage of elements in the following compound: K_(2)SO_(4) |
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Answer» SOLUTION :Molecular mass of `(K_(2)SO_(4)) = (2 xx "atomic mass of K") + (1 xx "atomic mass of S") + (4 xx "atomic mass of O")` `= (2 xx 39) + (1 xx 32) + (4 xx 16)` = 78 + 32 + 64 = 174 `:.` 174 g of `K_(2)SO_(4)` contains 78 g of POTASSIUM. 32 g of SULPHUR and 64 g of oxygen Percentage of potassium = `(78 g)/(174 g) xx 100 ~~ 44.83` Percentage of sulphur = `(32 g)/(174 g) xx 100 ~~ 18.39` Percentage of oxygen= `(64 g)/(174 g) xx 100 ~~ 36.78` Polassium : 44.83 %, Sulphur: 18.39% and Oxygen : 36.78 % |
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| 2588. |
Calculate the percentage of elements in the following compound: Ammonia |
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Answer» Solution :Molecular formula of AMMONIA is `NH_(3)`. Molecular mass of `NH_(3) = (1 xx "ATOMIC mass of N") + (3 xx "atomic mass of H")` `= (1 xx 14) + (3 xx 1)` = 14 + 3 = 17 `g//"MOLE"` Thus, in 17g `NH_(3)`, 14g of N and 3g of H is present. Percentage of nitrogen = `(14g)/(17g) xx 100` =82.35 Percentage of HYDROGEN =`(3g)/(17g) xx 100` = 17.65 Nitrogen : 82.35 % and Hydrogen : 17.65% |
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| 2589. |
Calculate the percentage of elements in the following compound: Ethanol (C_(2)H_(5)OH) |
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Answer» SOLUTION :Molecular MASS of Ethanol `(C_(2)H_(5)OH) = (2 xx "ATOMIC mass of C") + (6 xx "atomic mass of H") + (1 xx "atomic mass of O")` `= (2 xx 12) + (6 xx 1) + (1 xx 16)` = 24 + 6 + 16 = 46 `g//"mole"` `:.` 46 g of ethanol contains 24G carbon, 6g hydrogen and 16 g oxygen. Percentage of carbon =`(24g)/(47g) xx 100 ~~ 52.174` Percentage of hydrogen = `(6 g)/(46 g) xx 100 ~~ 13.043` Percentage of oxygen =`(16 g)/(46 g) xx 100 ~~ 34.783` Carbon: 52.174 %. Hydrogen: 13.043 % and Oxygen : 34.783 % |
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| 2590. |
Calculate the percentage composition of (i) iron in ferric oxide , Fe_(2)O_(3) (atomic mass of Fe = 56) (ii) nitrogen in urea H_(2)NCONH_(2) |
| Answer» SOLUTION :(i) 70% (II) 46.6 % | |