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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.
| 5451. |
How do alkanes, alkenes and alkynes differ from each other with respect to Reaction with bromine water |
| Answer» Solution :Alkanes do not AFFECT BROMINE water, WHEREAS alkenes and alkynes decolourise it. | |
| 5452. |
How do alcohol affect living beings? Explain. |
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Answer» Solution :When a large quantity of ethanol is consumed, it tends to slow down metabolic processes. Moreover, it DEPRESSES the Central Nervous SYSTEM (CNS). This results in LACK of coordination, mental confusion, drowsiness, lowering of the normal inhibitors and finally individual becomes unconscious and lethargic. The individual may feel relaxed but does not realised that his sense of JUDGEMENT, sense of timing and muscular coordination have been seriously impaired. Instead of ethanol, intake of methanol in very small quantities can cause death, because methanol is oxidised to methanal in liver. Methanal reacts rapidly with the COMPONENTS of cells and coagulates the protoplasm. Methanol also affects the optic nerve and causes blindness. Thus, consumption of alcohol is dangerous to living beings. |
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| 5453. |
How do alkanes, alkenes and alkynes differ from each other with respect to General formula |
| Answer» SOLUTION :Alkanes` = C_2H_(2n+2) ` , ALKENES ` = C_2H_(2n)` , ALKYNES ` = C_2H_(2n - 2)` | |
| 5454. |
How do alkanes, alkenes and alkynes differ from each other with respect to Nature of bonds between carbon atoms |
| Answer» SOLUTION :Alkanes: Only SINGLE bonds, ALKENES: At LEAST one C=C bond, Alkynes: At least one `C-=C` bond | |
| 5455. |
How dirt is washed away with the soap? |
| Answer» Solution :When a soap or detergent is dissolved in water, the molecules join together a clusters called micelles. Their long hydrocarbon chain attach themselves to the oil and dirt. The dirt is thus SURROUNDED by the non-polar end of the soap molecules. The CHARGED carboxylate end to the soap molecules MAKES the micelles soluble in water. Thus the dirt is WASHED away with the soap. | |
| 5456. |
How did the position of _17^35Cland _17^37Cl get fixed in the Modern Periodic table? |
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Answer» Solution :(i) Modem PERIODIC table is based on ATOMIC numbers, So, the position of ISOTOPES of elements was decided by arranging the elements in the ascending order of their atomic numbers. (ii) As isotopes have the same atomic number they do not need to be given DIFFERENT POSITIONS (slots). |
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| 5457. |
How did the study of large number of elements become easy? |
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Answer» Solution :The substance around us exist in the form of elements, compounds and mixtures. Elements consist of only one TYPE of atoms. There are 118 known elements at present, in which 98 elements occur naturally. Different elements have different properties. As more and more elements were being DISCOVERED, scientist gathered more and more information about the properties of newly discovered elements. THEREFORE, scientist felt the necessity to ORGANISE these information and started looking for some pattern in the properties of elements. Thus, the study of large number of elements became easy on the basis of specific patterns in their properties and their ARRANGEMENT. |
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| 5458. |
How did sommerfeld explain the fine sturcture of hydrogen spectrum ? |
| Answer» SOLUTION :Sommerfeld suggested that the SUB-energy LEVELS or subshells associated with each main energy level are responsible for fine structure of hydrogen spectrum.These sub -energy levels or subshells EXIST due to the difference in the energies of the ELECTRONS revolving in different elliptical orbits belonging to the same main energy level. | |
| 5459. |
How did Sommerfeld explain the fine structure of hydrogen spectrum? |
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Answer» Solution : ANGULAR momentum,`MVR=(nh)/(2PI)` `therefore 5.27xx10^(-34)=(nxx6.625xx10^(-34))/(2xx(22)/7)rArrn=5S` `"Radius" r_n=(0.529xxn^2)/Z Å` `=(0.529xx25)/3=4.408 Åor 4.408xx10^(-8) cm` |
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| 5460. |
How did Mendeleev arrange the elements? He left empty places in his periodic table. Why? Explain the limitations of Mendeleev classification |
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Answer» Solution :a) Mendeleev REALIZED that the physical and chemical properties of elements were related to their atomic mass in a "periodic way and arranged them so that groups of elements with SIMILAR properties fell into vertical columns in his table. b) Gaps were left for undiscovered elements in the Mendeleev.s periodic table. c) Limitations of Mendeleev classification : * Position of hydrogen was not justified. * INCREASING ORDER of atomic mass could not be maintained. * Isotopes have similar chemical properties but different atomic masses, they cannot be given separate places. * Mendeleev could not EXPLAIN the cause of periodicty. |
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| 5461. |
What were the limitations of Dobreiner's classification? |
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Answer» Solution :He CLASSIFIED in group of three such that atomic No. of middle ELEMENTS is average of first and third element. Eg: Li(7), Na(23), K(39), Limitations : * Dobereiner could find only three triads, i.e. TOTAL of 9 elements only. * However the total number of elements were more than that of those encompassed in Dobereiner.s triad. * THUS Dobereiner could not classify most of the elements known at that time.. |
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| 5462. |
How could the Modem Periodic Table remove various anomalies of Mendeleev's table? |
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Answer» Solution :(i) The Modem Periodic Table was classified on the basis of atomic number. All isotopes of the same elements have different masses but same atomic number . THEREFORE, they occupy the same position in the Modem Periodic table. (ii) When elements are arranged according to their atomic numbers, the anomaly regarding certain pairs of elements in Mendeleev.s Periodic Table disappears e.g. atomic number of cobalt and nickel are · 27 and 28 respectively. Therefore, cobalt will come first and then nickel, ALTHOUGH atomic MASS of cobalt is greater . (iii) Elements are classified according to their electronic configuration into different blocks. (iv) Hydrogen has one electron in the outermost SHELL. It is placed on top of the GROUP 1 with alkali metals which have one electron in the outermost shell. This is because in the Modem Periodic Table elements are arranged on the basis of electronic configuration. |
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| 5463. |
How could the Modern Periodic Table remove various anomalies of Mendeleev's Periodic Table? |
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Answer» SOLUTION :With the adoption of atomic number as the basis of classification of elements, some of the anomaliesin the Mendeleev.s Periodic Table now DISAPPEAR. These are: (i) Position of hydrogen: The atomic number of hydrogen is 1 and hence, it should occupy thefirst position in group 1 of the Periodic Table. But, because of its chemical similarity with elements of group 1 and group 17, the position of hydrogen in the Periodic Table is stilldebated. (ii) Position of isotopes: As the isotopes of an element have the same atomic number, they should occupy the same place in the Periodic Table. (iii) Position of anomalous pair: The position of anomalous pair of elements, i.e., pair of elements in which the element with higher atomic mass PRECEDES the clement with lower atomic mass is also decided. When these elements are arranged in order of their atomic numbers, they occupy their natural places in the Periodic Table as shown in following table. 
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| 5464. |
How could the Modem Periodic Table remove various anomalies of Mendeleev's Periodic Table? |
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Answer» Solution :(i) Modern PERIODIC Table settled the controversial POSITION of HYDROGEN. (ii) The QUESTION of placement of ISOTOPES of an element in the Periodic Table was answered by Modern Periodic Table. |
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| 5465. |
How concentrated sulphuric acid can be diluted ? Describe the process. |
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Answer» Solution :While diluting concentrated sulphuric acid, water is not added to the acid. Rather acid is added to water. TAKE some water in a BEAKER. Add conc. Sulphuric acid in SMALL LOTS to water. Stir the mixture with glass ROD constantly. Cool the beaker under water is it becomes hot . |
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| 5466. |
How concentrated sulphuri acid can be diluted ? Describe the process. |
| Answer» Solution :Take water in a beaker. Add to it small AMOUNT of CONCENTRATED sulphuric acid with SHAKING with the HELP of a glass stirrer. Cool the beaker in water taken in a trough, if it becomes hot. Continue adding sulphuric acid in a similar manner till the whole of sulphuric acid has been DILUTED. | |
| 5467. |
How clectronegativity values help to find out the nature of bonding between atoms? |
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Answer» Solution :If the DIFFERENCE in clectronegativity between TWO clements is 1.7, the bond has 50% ionic character and 50% COVALENT character. (ii) If the difference is less than 1.7, the bond is considered to be covalent. (III) If the difference is greater than 1.7, the bond is considered to be ionic. |
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| 5468. |
The particles of a substance suspended in a suspension can be separated by |
| Answer» Solution :The PARTICLES of a SOLUTE can be SEPARATED from a SUSPENSION by the process of filtration | |
| 5469. |
How can you separate solid particles present in a heap of grains such as wheat ? |
| Answer» SOLUTION :By WINNOWING . | |
| 5470. |
How can you convert methane into chloroform by a substitution reaction? Explain with the help of a chemical equation. |
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Answer» Solution :Methane undergoes substitution REACTION with excess of chlorine gas in the presence of sunlight to give chloroform. The reaction involves gradual REPLACEMENT of HYDROGEN, one atom at a time. `CH_4 + Cl_2 overset("LIV")(rarr) underset("Chloromethane")(CH_3Cl) + HCL` `CH_3Cl + Cl_2 overset("liv")(rarr) underset("Dichlomethane")(CH_2Cl_2) + HCl` `CH_2Cl_2 + Cl_2 overset("liv")(rarr) underset("Chloroform") + HCl` |
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| 5471. |
How can you as an individual contribute or make a different to the management of a) Forests and wildlife b) Water resources and c) Coal and petroleum |
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Answer» Solution :a) Forests and wildlife Take part in community activities with focus on conserving forests and wildlife As a tourist follow all principles of conservation Help organisation ENGAGED in conservation of forests and wildlife. b) Water RESOURCES SAVE water in domestic use. Install a system for rainwater harvesting c) Coal and petroleum Save electricity Install electric gadgets that use LESS power Use public transport. |
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| 5472. |
How can the rusting of iron be prevented ? |
| Answer» Solution :The RUSTING of iron can be prevented by PAINTING, OILING, greasing, chrome plating, anodising or by MAKING alloys. | |
| 5473. |
How can the metal be obtained from its carbonate ore? |
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Answer» Solution :The carbonate ore is first heated STRONGLY in LIMITED supply of oxygen and changed into its oxide. This process is called calcination. `ZnCO_3(s) to^(Heat)ZnO(s)+CO_2(g)` ZINC oxide is then reduced to zinc METAL by HEATING it with carbon. This process is called reduction. `ZnO(s)+C(s) to^(Heat)Zn(s)+CO(g)` |
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| 5474. |
How can three resistors of resistances 2Omega,3Omegaand6Omega be connected to give a total resistance of a] 4Omega. b] 1Omega ? |
| Answer» Solution :Ant.s sting can be NEUTRALISED by the addition of soap or baking soda. NETTLE sting can be neutralised by rubbing the LEAF of DOCK plant in that area. | |
| 5475. |
How can the black coating of copper oxide be removed chemically ? |
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Answer» Solution :The black coating of copper oxide can be removed chemically by passing the HYDROGEN GAS over heated copper oxide. As a RESULT, the black coating turns brown in colour as oxygen is removed by hydrogen. `CuO+ H_(2) to Cu+H_(2)O` |
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| 5476. |
How can plants and trees be used to obtain a number of chemicals ? |
| Answer» Solution :Cellulose present in plants and trees can be FERMENTED to PRODUCE ethanol, butanol, ACETONE, methane and SEVERAL other substances. | |
| 5477. |
How can ethanol and ethanoic acid be diffrerentiated on the basis of their physical and chemical properties ? |
Answer» SOLUTION :DIFFERENCE in PHYSICAL PROPERTIES :  Difference in CHEMICAL properties : 
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| 5478. |
How can ethanal and ethanoic acid be differentiated on the basis of their physical and chemical properties? |
Answer» SOLUTION :
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| 5479. |
How can a layer of aluminium oxide on an aluminium object be made thicker? What is the process called? |
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Answer» Solution :Aluminium develops a thin oxide layer WHNE exposed to air. This aluminium oxide coat makes it resistant to further corrosion. The resistance can be improved further by MAKING the oxide layer thicker. This process is called anodising. During anodising, a clean aluminium article is MADE the anod and is electrolysed with dilute sulphuric acid. The oxygen gas evolved at the ANODE REACTS wiht aluminium to make a thicker protective oxide layer. This oxide layer can be dyed easily to give aluminium articles an attractive finish. |
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| 5480. |
How can a chemical equation be made more informative ? |
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Answer» Solution :(a) By INDICATING the physical states of the reactants and products (b) By using an upward arrow to INDICATE the evolution of a gaseous product (C) By using a cownward arrow to indicate the formation of a precipitate (d) By indicating the aqueous solutions as (aq.) (e) By indicating the energy changes `C_(6)H_(12)O_(6)(s)+6O_(2)(g)to6CO_(2)(g)+6H_(2)O(L)+"energy"`. |
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| 5481. |
How are the noble metals containing other metals as impurities purified? |
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Answer» Solution :(i) Reactivity of noble metals. (ii) COMPARISON of reactivity of noble metals with other metals. (III) Separation TECHNIQUE adopted for the removal of impurities fromthe noble metal BASED on the differenties in reactivity. |
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| 5482. |
How are the following related ? a)Number of valence electrons of different elements in the same group. b) Number of shells of elements in the same period. |
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Answer» Solution :(a) Different elements in same GROUP have same NUMBER of valence electrons. (b)Number of SHELLS of elements in same period are EQUAL. |
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| 5483. |
How are the following products obtained from ethanol ? (i) Ethyl ethanoate (ii) Sodium ethoxide. |
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Answer» Solution :(i) Ethanol reacts with ethanoic acid in the presence of acid CATALYST to GIVE ethyl ethanoate. `CH_(3)COOH + CH_(3)CH_(2)O+ CH_(3)COOCH_(2)CH_(3)+H_(2)O overset("Acid") underset("Catalyst")rightarrow` (ii) When ethanol reacts with sodium, sodium ethoxide is produced along with the liberation of HYDROGEN. `2CH_(3)CH_(2)OH + 2Na rightarrow 2CH_(3)CH_(2)ONa+H_(2)` |
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| 5484. |
How are the alveoli designed to maximise the exchange of gases? |
| Answer» Solution :There are MILLIONS of thin walled air sacs called alveoli in the lungs. The presence of these alveoli provides a large area for exchange of gases the availability of large SURFACE area maximises the exchange of gases for example if all the alveoli from two human beings are unfolded they WOULD give an area of about 80 square METRES. | |
| 5485. |
How are salts formed ? What determines their pH value in aqueous solutions ? |
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Answer» Solution :Salts are FORMED when an ACID and a BASE react with each other (neutralisation reaction). Their PH value is determined by the kind of the acid and the base that combine to form the salt. If both the acid and the base are strong then the RESULTING salt would be neutral salt (pH = 7) If the acid involve d is strong while the base is weak, then the salt would be an acidic salt `(pH lt 7)`. If the acid is weak and the base is strong, then the salt would be a basic salt `(pH gt 7)`. |
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| 5486. |
How are isotopes of different elements placed in the Modem Periodic Table? |
| Answer» Solution :ISOTOPES have same atomic number, but different atomic mass. In MODERN Periodic table the elements are arranged in the increasing order of their atomic NUMBERS. So, all isotopes of an element can be GIVEN the same POSITION. | |
| 5487. |
How are ionic compounds formed ? |
| Answer» SOLUTION :Compounds FORMED by the TRANSFER of ELECTRONS from one atom to the other, are CALLED ionic compounds. | |
| 5488. |
How are general growth and sexual maturation different from each other? Which are the symptoms observed in sexually matured females? When a matured female receives male sex cells due to sexual contact what changes will happen in her uterus? |
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Answer» Solution :General growth is the growth of the human body such as increase in height, weight, change in shape and size. Sexual maturation refers to the CHANGES that the human body undergoes at puberty like change of VOICE in males, breast development in females, menstruation in female, growth of hair in public region etc. Increase in breast size. Broadening of hips. APPEARANCE of hair under the armpits and in the GENITAL area. Beginning of menstrual cycle (uterus and ovary ENLARGE, ovary starts releasing egg) Pimples on skin appear due to secretion of oil from the skin. Once the zygote is implanted in the uterine wall, several changes takes place in the uterus. Uterus prepares itself to receive and nature the growing embryo. The uterine lining thickens and is richly supplied with blood to give support and nourishment to the growing embryo. |
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| 5489. |
How are fats digested in our bodies ? Where does this process take place ? |
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Answer» Solution :Digestion of fats takes place in the small INTESTINE the fats are digested by the digestive enzymes. The fats arc present in the from. of large globle in the small intestine. Bile juice sccreted by the liver is produced in the intestine along. pulureatic juice. The bile salts present in the bile juice emulsify the large globles of fats. So by cmulsification large globles breakdown into fine globules to PROVIDE large surface arca to act upon by the enzymes: ENZYME present in the pancratic juice cause breakdown of emusified fats. Glands present in the WALL of small intestine SECRETES intestinal juice which contains lipase enzyme that converts fats into faty acids and glyccrol. |
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| 5490. |
How are detergents prepared ? |
| Answer» SOLUTION :Detergents are prepared by TREATING hydrocarbons OBTAINED from petroleumwith conc. SULPHURIC acid . | |
| 5492. |
How are carboxylic acids different from mineral acids from ionisation point of view? |
| Answer» SOLUTION :Carboxylic acids (like `CH_(3)COOH`) ionise to a very small extent in solution and give very small AMOUNT of `H^(+)` ions. Thus, they are WEAK acids as compared to the mineral acids. | |
| 5493. |
How are bases different from alkalis ? Are all bases alkalis ? |
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Answer» Solution :Bases which are soluble in water and produce `OH^-` IONS are called alkalis. Some EXAMPLES are : `NAOH rarr Na^+ OH^-` Potassium hydroxide `KOH rarr K^(+) + OH^(-)` All alkalis are bases but all bases are not alkalis. For examples `Al(OH)_(3)` is BASE but not an alkali. |
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| 5497. |
Homogenous mixture is formed by mixing |
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Answer» PHENOL and water |
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| 5498. |
HNO_3 is reduced in…. |
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Answer» NO |
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| 5499. |
Hitarthi saw her grandmother storing pickles in ceramic pots. She also knew that pickles should not be stored in metal containers. Her friend often brought pickles wrapped in aluminium foil. Hitarthi advised her not to wrap pickles in foil. What value of Hitarthi is seen in the above act ? |
| Answer» Solution :HITARTHI SHOWED the VALUE of awareness and responsible CITIZEN. | |
| 5500. |
Hitarthi saw her grandmother storing pickles in ceramic pots. She also knew that pickles should not be stored in metal containers. Her friend often brought pickles wrapped in aluminium foil. Hitarthi advised her not to wrap pickles in foil. Which substances present in pickles reacts with the metal containers ? |
| Answer» SOLUTION :Pickles are SOUR in taste and CONTAINS acidic nature. Thus, they react with the METAL CONTAINERS. | |