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This section includes 7 InterviewSolutions, each offering curated multiple-choice questions to sharpen your Current Affairs knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Silicon is an important constituent ofa) chlorophyllb)Heamoglobinc)Rocksd)Amalgams |
| Answer» Rocks | |
| 2. |
Which is not a natural polymer? Wool\xa0SilkLeatherNylon |
| Answer» Nylon | |
| 3. |
The number of waves made by a bhor electron in an orbit of maximum magnetic quantum number +2..... |
| Answer» No of waves are 3\xa0 | |
| 4. |
what are hybridisation state of each carbon atom in CH3=CH--C and triple bond of nitrogen\xa0 |
| Answer» the question written over is incorrect.the actual molecule should be like this H2C=CH-CH3in the case of above molecule the C1=SP2\xa0hybridisationC2=SP2\xa0hybridisationC3=SP3 hyridisation | |
| 5. |
Find the volume of ammonia gas at NTP |
| Answer» | |
| 6. |
differences between pure substance and mixture? |
| Answer» Ans.\tPure Substance has the same composition and properties throughout Whereas Mixture is the combination of two or more pure substances where each substance retains its own identity.\tPure substances cannot be separated into any other kinds of matter, while a mixture is a combination of two or more pure substances.\tA pure substance has constant physical and chemical properties, while mixtures have varying physical and chemical properties (i.e., boiling point and melting point).\tA pure substance is pure, while a mixture is impure.\te.g: Pure water is a pure substance. It consist of only water molecules While e.g: Alcohol-water mixture, both co-exist together. | |
| 7. |
Find no. of moles in 44.8 litres of CO2 at STP |
| Answer» At STP, one mole of gas has a volume of 22.4 liters.Given that there are 44.8 liters in this problem, which is twice as much as 22.4, there must be 2.00 moles of Carbon Dioxide CO2\xa0gas. | |
| 8. |
Calculate the no. of atoms of the constituent elements in 53g of Na2CO3 |
| Answer» Molecular mass of Na2CO3\xa0= ( 2 × 23 ) + 12 + (3 × 16) = 46 + 12 + 48 = 106\xa0Given mass of Na2CO3\xa0= 53 g106 g of Na2CO3\xa0Contain = 1 mol53 g of Na2CO3 Contain = {tex}{53\\over 106} = {1\\over 2}{/tex}\xa0mol \xa0No of atoms of Na =\xa0{tex}{1\\over 2}\\times 2 \\times 6.022 \\times 10^{23}{/tex}=\xa0{tex} 6.022 \\times 10^{23}{/tex}No of atoms of C =\xa0{tex}{1\\over 2}\\times 6.022 \\times 10^{23}{/tex}=\xa0{tex}3.011 \\times 10^{23}{/tex}No of atoms of O =\xa0{tex}{1\\over 2}\\times 3 \\times 6.022 \\times 10^{23}{/tex}=\xa0{tex}9.033\\times 10^{23}{/tex}\xa0 | |
| 9. |
5 differencesbetween a pure substance and a mixture |
| Answer» \tPropertiesPure SubstanceMixtureDefineThe substances that are made of a single element or compound are called pure substancesSeveral elements & compounds together form a mixtureCategorizationSolid, liquid, gasHeterogeneous, homogeneousPhysical propertiesConstantVaryPurityPureImpureSeparation by a physical processNot possiblePossible to separate by evaporation, magnetic separation, etc.Chemical propertiesConstantVaryExampleGold, pure water, hydrogen gasOil & water, sand & sugar\t | |
| 10. |
Calculate the molarity of water. If density of water is 1g per ml. |
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Answer» Thanku very much Ans. 1 liter water =1 Kgor 1000 ml water = 1 Kg\xa0Given density of Water (d) =1g/ml = 1kg/LMass of 1 Litre of water = Density of water * Volume = 1 * 1 = 1 Kg = 1000g\xa0\xa0Moles of water present in 1L = {tex}1000\\over 18{/tex}\xa0=\xa055.55 Hence Molarity of water = 55.55 M\xa0 |
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| 11. |
How many triads doberieneir gave\xa0 |
| Answer» Doberieneir gave 3 triads\tLi Na K\tCl Br I\tCa Sr Ba | |
| 12. |
How much copper can be obtained from 100g of copper sulphate ? |
| Answer» Ans. 1 mole of CuSO4 provides 1 mole Of Cu.Hence 159.5 g of CuSO4\xa0{tex}\\to {/tex}\xa063.5 g of Cu( molar mass of CuSO4\xa0is 159.5 and cu is 63.5)So 100 g of CuSO4\xa0ll produce\xa0{tex} {63.5\\times 100 \\over 159.5}{/tex}= 39.8g | |
| 13. |
Which book we should prefer in class 11.NCERT publication or private books. |
| Answer» | |
| 14. |
derive the equation Kp=Kc(RT) |
| Answer» | |
| 15. |
calculate volume of 4.4 g of CO2 at stp |
| Answer» Ans. No. of moles of CO2\xa0present=given mass /molar mass=> 4.4/44 = 0.1 molesNo. of moles = given vol. / 22.4 litres=> 0.1= given vol./22.4 litres=> 0.1*22.4 = given vol.Given vol is the required vol. here,So the vol. occupied by 4.4g of CO2\xa0is 2.24 litres. | |
| 16. |
Why molecules of larger size can be easily polarized ? |
| Answer» Ans. In large ions, the charge is distributed over a large area, because of which the charge per unit volume is less. Therefore the hold of the nucleus on the outermost electrons is less, because of which the electronic distribution in these ions can be easily disturbed (or they can be easily polarised), when a small ion comes closer to these ions. | |
| 17. |
why amminoa has higher dipole momentvthan nf3\xa0 |
| Answer» Ans.\xa0This is due to the fact that dipole moment is a vector quantity and hence resultant dipole moment in a molecule will depend upon the direction of dipole moments of individual bonds.Nitrogen has a lone pair of electrons and is more electronegative than hydrogen. So, in case of NH3, the orbital moment due to the lone pair of electrons on nitrogen is in the same direction of the 3 N-H dipoles.Thus, the molecule has a net dipole moment and it is polar.In NF3, fluorine being more electronegative than nitrogen pulls the shared pair of electrons of the N-F bonds towards itself. Because of this, the orbital moment\xa0due to lone pair of electrons and the resultant dipole moment of 3 N-F bonds point in the opposite directions to\xa0that of lone pair of electrons. This lowers the dipole moment of NF3. | |
| 18. |
Which element used in photoelectric cell |
| Answer» Caesium (Cs) Since it has low ionisation enthalpy. | |
| 19. |
. Which species is the smallest aromatic substance? |
| Answer» The cyclopropenyl cation is the smallest aromatic substance.As to π electrons, when n = 0, the ordinary cyclopropene molecule is not aromatic. It becomes aromatic only if the third π electron is missing. That is, when it becomes the cyclopropenyl cation and its ring has a positive charge. | |
| 20. |
explain haeber\'s process |
Answer» The process converts atmospheric\xa0nitrogen\xa0(N2) to ammonia (NH3) by a reaction with\xa0hydrogen\xa0(H2) using a metal catalyst under high temperatures and pressures:
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| 21. |
What is hydro\xa0 |
| Answer» hydro what??\xa0\xa0 | |
| 22. |
Describe the structure of benzene\xa0 |
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Answer» The usual structural representation for benzene is a six carbon ring (represented by a hexagon) which includes three double bonds. Each of the carbons represented by a corner is also bonded to one other atom. In benzene itself, these atoms are hydrogens. The double bonds are separated by single bonds so we recognize the arrangement as involving conjugated double bonds. An alternative symbol uses a circle inside the hexagon to represent the six pi electrons. Each of these symbols has good and bad features. We\'ll use the three double bond symbol simply because it is also routinely used in the text. |
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| 23. |
electrode potential |
Answer» Electrode potential,\xa0E, in chemistry or\xa0electrochemistry, according to a\xa0IUPAC\xa0definition,[1]\xa0is the\xa0electromotive force\xa0of acell\xa0built of two\xa0electrodes:\ton the left-hand side is the\xa0standard hydrogen electrode, and\ton the right-hand side is the electrode the potential of which is being defined.By\xa0convention:
Electrode potential is defined as the potential of a cell consisting of the electrode in question acting as a cathode and the standard hydrogen electrode acting as an anode. Reduction always takes place at the cathode, and oxidation at the anode. |
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| 24. |
How can you explain higher stability of BCl3 as compared to TlCl3 |
| Answer» Both boron and thallium belong to group 13 of the periodic table. Boron does not show inert pair effect as it does not have d or f electrons. As we go down the group, the shielding effect of the electrons also decrease therefore the increased nuclear charge down the group is not neutralized by the poor shielding effect of the electrons in the inner orbitals.Due to this the inert pair effect becomes more and more predominant and the s electrons of the valency shell experiences strong attraction .This effect is maximum in thallium and therefore only the 6p1 electrons take part in the bond formation. This makes +1 oxidation state most stable in case of thallium. Therefore TlCl is stable and TlCl3 is unstable. In case of BCl3 , boron does not have d or f orbital , so all the valence electron in the 2s and 2p orbital takes part in the bond formation making BCl3 stable. | |
| 25. |
What is the active mass of water\xa0 |
| Answer» Active mass\xa0is defined as the molar concentration ie. number of Gram-moles per litreActive mass for pure liquids and solids is Always taken 1.if not pure water thenFor water,\xa0density = 1 g/mL = 1000 g/L\xa0Molar mass = 18.015 g/mol\xa0so\xa01000 g/L = (1000 g/L)/(18.015 g/mol) = 55.51 mol/L | |
| 26. |
Nacl is soluble in water and insoluble in petrol why?\xa0 |
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Answer» Just remember that like dissolves like. The same way, polar dissolves polar compounds. In this case, NaCl is polar so it gets dissolved in water(which we know is also polar). On the other hand, petroleum is a non polar compound, Therefore, NaCl does not dissolve in it.\xa0 Sodium chloride is an ionic molecule. There exists electronegativity difference between Sodium and Chlorine, which gives polarity to the molecule. Thus sodium chloride is polar molecule.Generally polar molecules will soluble in polar solvents and insoluble in non-polar solvents. Non-polar molecules will soluble in non-polar solvents and insoluble in polar solvents.As sodium chloride is polar molecule it will be soluble in polar solvents like water. And insoluble in petrol (as it is non-polar solvent). |
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| 27. |
Why does the colour of NaCl chage into blue whe we add some lemon juice?\xa0\xa0 |
| Answer» | |
| 28. |
Why the salts of superoxides are coloured? |
| Answer» They are coloured because of paramagnetic nature of the compound O2-.According to molecular orbital theory it has an unpaired electron hence it is paramagnetism. | |
| 29. |
Why diffusion is not in the case of earth with respect to space whether earth has many gases?\xa0 |
| Answer» | |
| 30. |
What is polarity\xa0 |
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Answer» Polarity is separation of electric charge leading to a molecule having electric dipoles.polar molecule interact through intermolecular forces.for example H2O is a polar molecule but CO2 is non polar molecule in which dipoles cancel each other. Polarity is a physical property of compounds which relate to other physical properties, such as melting and boiling points or solubility.\xa0Bond polarities arise from bonds between atoms of different electronegativity. A molecule can be ionic, polar or non-polar.A polar molecule is formed when one end of a molecule has a positive charge and the opposite end has a negative charge, thus creating electrical poles. A non-polar molecule does not have charges at the ends as the electrons are distributed more symmetrically and cancel each other out.When trying to create a solution, a polar molecule does not mix with a non-polar molecule. An example of this is seen with water, a polar molecule and oil, anon-polar molecule; the two molecules cannot mix to form a solution. However, water and alcohol can mix to form a solution as they are both polar molecules. |
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| 31. |
how to give iupac name to organic compounds |
| Answer» IUPAC naming involves certain set of rules.The first step is to identify the longest carbon chain and name it as alkane,alkene or alkyne depending upon the bond if it is single, double or triple bond. The alkane chain when used as substituent is named as alkyl group.\xa0Name the carbon chain such that the substituents get the least position.The type of group attached to the carbon chain will decide the suffix attached to the IUPAC name.A cyclic compound is designated by prefix cyclo group attached to it.\xa0 | |
| 32. |
what is the canonical structure for NO3+ |
| Answer» | |
| 33. |
what is balancing? |
| Answer» Balancing of reaction means making the number of atoms equal on both sides of the reaction( reactants and products) .We move step by step to write a balanced equation making number of atoms equal on both sides. | |
| 34. |
what do you mean by ionisation enthailpy and atomic radiii/????????\xa0\xa0 |
| Answer» The amount of energy required to remove one electron from outermost shell of an atom is called ionisation enthailapy. The distance between the nulceus the outermost shell is called atomic radius. | |
| 35. |
What is normality?? |
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Answer» Normality is defined as number of grand equivalent of solute dissolved per litre of solution . the equivalent mass required for it is defined as molecular mass divided by acidity/basicity of salt/ valence electrons/ electrons list or gained in redox rxn depending upon the type for which we are finding equivalent mass. Normality of a solution is the gram equivalent weight of solute per litre of solution. |
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| 36. |
formula for finding mass %\xa0 |
| Answer» Mass% = Mass of solute / mass of solution X100% | |
| 37. |
Whose bond angle ( F-C-F ) is greater - CH2F2\xa0or CHF3\xa0??? Explain with reason.\xa0 |
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Answer» shm dar important chapter hai\xa0 The C-H and C-F bonds are polar and so the electron density will be shifted towards carbon in the C-H bonds and towards fluorine in the C-F bonds. Directing orbitals with more s character towards the hydrogens is stabilizing, while directing orbitals of less s character towards the fluorine is destabilizing but to a lesser extent. |
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| 38. |
how to draw lewis dot structure of NO2? |
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Answer» We take the number if valence electrons in each of the atom and draws it to complete the octet.the nitrogen carries one negative charge making it having 5+1=6 Valene electrons .thus the structure becomesO = N - O O-N=O |
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| 39. |
harmful effects of cold drinks?\xa0 |
| Answer» Artificial Sweeteners– In diet sodas, aspartame is used as a substitute for sugar, and can actually be more harmful. It has been linked to almost a hundred different health problems including seizures, multiple sclerosis, brain tumors, diabetes, and emotional disorders. It converts to methanol at warm temperatures and methanol breaks down to formaldehyde and formic acid. Diet sodas also increase the risk of metabolic syndrome, which causes belly fat, high blood sugar and raised cholesterol.Phosphoric Acid\xa0-Soda contains phosphoric acid, which interferes with the body’s ability to absorb calcium and can lead to osteoporosis, cavities and bone softening. Phosphoric Acid also interacts with stomach acid, slowing digestion and blocking nutrient absorption.\xa0The Sugar!\xa0– A single can of soda contains the equivalent of\xa010 teaspoons of sugar. This amount of sugar, especially in liquid form,\xa0skyrockets the blood sugar and causes an insulin reaction in the body. Over time, this can lead to diabetes or insulin resistance, not to mention weight gain and other health problems. Soft drink companies are the largest user of sugar in the country.\xa0Caffeine– Most sodas contain caffeine, which has been linked to certain cancers, breast lumps, irregular heart beat, high blood pressure, and other problems.The Water– The water used in soda is just simple tap water and can contain chemicals like chlorine, fluoride and traces of heavy metals.Obesity– Harvard researchers have recently positively linked soft drinks to obesity. The study found that 12 year olds who drank soda were more likely to be obese than those who didn’t, and for each serving of soda consumed daily, the risk of obesity increased 1.6 times.Extra Fructose– Sodas contain High Fructose Corn Syrup, which obviously comes from corn. Most of this corn has been genetically modified, and there are no long term studies showing the safety of genetically modified crops, as genetic modification of crops has only been around since the 1990s. Also, the process of making High Fructose Corn Syrup involves traces of mercury, which causes a variety of long term health problems.Lack of Nutrients– There is absolutely no nutritional value in soda whatsoever. Not only are there many harmful effects of soda, but there are not even any positive benefits to outweigh them. Soda is an unnatural substance that harms the body.Dehydration– Because of the high sugar, sodium and caffeine content in soda, it dehydrates the body and over a long period of time can cause chronic dehydration.Bad for the teeth– Drinking soda regularly causes plaque to build up on the teeth and can lead to cavities and gum disease.\xa0 | |
| 40. |
how to introduce a triple bond b/w two carbon atoms |
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Answer» 1. Dehydrohalogenation of vicinal or geminal dihalides: A vicinal di halide such as 1,2 dichloroethane when treated with sodamide(NaNH2) yields Ethyne.\xa02.Dehalogenations of tetrahaloalkanes.3.From Calcium Carbide:Higher homologues can be prepared by nucleophilic displacement by acetylide anion. Secondary halodes gives poor yield while tertiary halides cannot be used.4.By heating Iodoform with silver:2CHI3+6Ag→heatC2H2+6Ag You can get your doubts cleared instantly, 24/7 with IIT/AIIMS tutors on HashLearn. Download here: http://bit.ly/2fDYZtb |
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| 41. |
Give two reactions to show acidic character of alkynes? |
| Answer» 1.Formation of sodium acetylides.C2H2→NaHC≡CNa→NaNaC≡CNa2.Formation of copper acetylide.C2H2+2AgNO3+NH4OH→AgC≡CAg+2NH4NO3+2H20 | |
| 42. |
which isotope of hydrgen is radioactive |
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Answer» There are three isotopes of protium, deuterium and tritium .out of the three isotopes, tritium is the isotope which is radioactive in nature and it is used in spectroscopy. Deuterium\xa0is a hydrogen isotope consisting of one proton, one neutron and one electron. It has major applications in nuclear magnetic resonance studies.\xa0Tritium\xa0is a hydrogen isotope consisting of one proton, two neutrons and one electron. It is radioactive, with a half-life of 12.32 years. |
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| 43. |
"BeH2 molecules has zero diopole moment althrough the Be-H bonds are polar" Explain |
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Answer» The Be-H bonds are polar due to electronegativity difference in them but the molecule BeH2 is non polar because the structure of BeH2 is linear where both Be-H bonds are opposite to each other and cancels each others polarity making it a non polar molecules with dipole moment zeroH<---Be-->H The dipole moment of BeH2\xa0has 0 because the two equal bond dipole are present in opposite directions and cancel the effect of each other.H↤Be↦H |
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| 44. |
What do you mean by hydride gap? |
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Answer» The metals of 7th, 8th and 9th groups in the periodic table do not form hydrides\xa0and this region of periodic table is referred to as the hydride gap. The metals of group 7,8,9 of the periodic table do not form hydrides as they have low affinity to combine with hydrogen in their normal state.This region is called hydride gap. |
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| 45. |
Calculate pH for 0.001M NaOH |
| Answer» NaOH is a strong base that dissociates completely\xa0Therefore [OH-] = [NaOH] = 0.001M\xa0First calculate the pOH of the solution :\xa0pOH = -log [OH-]\xa0pOH = -log 0.001\xa0pOH = 3.00\xa0pH = 14.00 - pOH\xa0pH = 14.00 - 3.00\xa0pH = 11.00 | |
| 46. |
how hydrogen is different from halogens?\xa0 |
| Answer» Hydrogen is the lightest element having atomic mass 1 while halogens are group of elements that includes F, Cl, Br, I etc. Hydrogen acts as both electropositive and electronegative element but halogens are hightly electronegative in nature. | |
| 47. |
What ie photoelectric effect |
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Answer» Under the right circumstances light can be used to push electrons, freeing them from the surface of a solid. This process is called the\xa0photoelectric effect\xa0(or\xa0photoelectric emission\xa0or\xa0photoemission), a material that can exhibit this phenomena is said to be\xa0photoemissive, and the ejected electrons are called\xa0photoelectrons; but there is nothing that would distinguish them from other electrons. All electrons are identical to one another in mass, charge, spin, and magnetic moment. The\xa0photoelectric effect\xa0or photoemission is the production of electrons or other free carriers when light is shone onto a material. Electrons emitted in this manner can be called photoelectrons. |
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| 48. |
Why lithium halides are somewhat covalent? |
| Answer» We know that, electronegative nature decreases down the group, so Li will have higher electronegative character than other elements of the group, and also it has very small size the lithium halides become covalent in nature.It is because, the small size of Li+\xa0cation will have the maximum tendency to withdraw electrons from anions and so it polarizes the bond and in this process, it distorts the electron clouds of anions which neutralizes some of the charge, and their increases a covalent character.The Fajan\'s rule explains that smaller the size of atom higher will be polarizing capacity and so the covalent character will be larger.So the Lithium halides become partially covalent in nature. | |
| 49. |
Why is Ga smaller in size than Al?\xa0 |
| Answer» The size of Ga is sampler than Al due to poor screening effect .The electrons in 3d of Ga are occupied ,they have poor screening effect and hence less influence to decrease effective nuclear charge .Therefore electrons in Ga experience more force of attraction than Al resulting in decrease in size. | |
| 50. |
what are heat capacities at constant volume and pressure?\xa0 |
| Answer» Ans.\xa0The heat capacity of anything tells us how much heat is required to raise a certain amount of it by one degree. For a gas we can define a molar heat capacity C - the heat required to increase the temperature of 1 mole of the gas by 1 K.Q\xa0=\xa0nC∆T\xa0The value of the heat capacity depends on whether the heat is added at constant volume, constant pressure, etc.CV, the heat capacity at constant volume, and CP, the heat capacity at constant pressure.Heat Capacity at Constant Volume CV:\xa0Q = nCVΔTFor an ideal gas, applying the First Law of Thermodynamics tells us that heat is also equal to:Q = ΔEint\xa0+ W, although W = 0 at constant volume.Heat Capacity at Constant Pressure:\xa0For an ideal gas at constant pressure, it takes more heat to achieve the same temperature change than it does at constant volume. At constant volume all the heat added goes into raising the temperature. At constant pressure some of the heat goes to doing work.Q = nCPΔTFor an ideal gas, applying the First Law of Thermodynamics tells us that heat is also equal to:Q = ΔEint\xa0+ WAt constant pressure W = PΔV = nRΔT | |