Explore topic-wise InterviewSolutions in Current Affairs.

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.	Define pH.
Answer» Solution :The pH is defined as, the logarithm to the base 10 of the RECIPROCAL of the MOLAR concentrations of HYDROGEN IONS.

2.	Define Percentage Composition in Compound.
Answer» Solution :So far, we were dealing with the number of entities PRESENT in a given sample, But many a time, the information regarding the percentage of a particular element present in a compound is required. One can check the purity of a given sample by analysing this data. Let us understand it by taking the example of water `(H_(2)O)`. Since water CONTAINS hydrogen and oxygen, the percentage composition of both these elements can be calculated as follows : Mass % of an element `=("mass of that element in the compound" xx 100)/("molar mass of the compound")` Molar mass of water `= 18.02g` Mass% of hydrogen `=(2xx1.008)/(18.02)XX100=11.18` Mass % of oxygen `=(16.00)/(18.02)xx100=88.79` The percentage of carbon, hydrogen and oxygen in ethanol : MOLECULAR FORMULA of ethanol is `=C_(2)H_(5)OH` Molar mass of ethanol `=(2xx12.01 + 6 xx 1.008+16.00)g` `=46.068g` Mass percent of carbon `=(24.02)/(46.068)xx100` `=52.14%` Mass percent of hydrogen `=(6.0489)/(46.0689)xx100` `=13.13%` Mass percent of oxygen `=(16.00 g)/(46.068 g)xx100` `=34.73%`

3.	Define oxidisingand reducing agents in terms of electrons
Answer» Solution :oxidising agents are electron acceptors while reducing agents are electron donor for EXAPLE oxidising agent : `MnO_(4)^(-)+ 8H^(+)+5e^(-)rarrMn^(2+)+4H_(2)O` Reducing agent :`Fe^(2+)rarr Fe^(3+)+e^(-)`

4.	Define oxidation number. What are the rules used to assign oxidation number?
Answer» Solution :Oxidation NUMBER REFERS to the number of charges an atom would have in a molecule or an ionic compound, if electrons were transferred completely. Rules to assign oxidation number: 1 Oxidation number of a substance in its elementary state is equal to zero `(H_(2), Br_(2)`, Na) 3 Oxidation number of a mono-atomic ION is equal to the charge on the ion `(Na^(+)=+1, S^(2-)=-2)`. 3. Oxidation number of hydrogen in a compound is +1 (except hydrides). 4. Oxidation number of hydrogen in metal hydrides is -1 (NaH, `CaH_(2))`. 5 Oxidation number of oxygen in a compound is -2 (except `OF_(2)` and peroxides). 6. Oxidation number of oxygen in peroxides is -1 `(H_(2)O_(2), Na_(2)O_(2))` = - 1. 7. Oxidation number of oxygen in fluorinated compounds is EITHER +1 or +2. `(OF_(2)` =+2,`O_(2)F_(2)` = +1). 8. Fluorine has an oxidation number -1 in all its compounds. 9. The sum of the oxidation number of all the atoms in neutral MOLECULES is equal to Zero. 10. For all ions, the sum of the oxidation number of all atoms is equal to the charge of the ion

5.	Define oxidation number. Balance the following equation using oxidation number method. As_(2)S_(3)+HNO_(3)+H_2O to H_3AsO_4+H_2SO_4+NO
Answer» Solution :Oxidation number : It is DEFINED as the imaginary the compound have been removed in their usual oxidation states that are assigned according to set of RULES. Step 1 : `As_(2)S_(3)+HNO_(3)+H_(2)OrarrH_(3)AsO_(4)+H_(2)SO_(4)+NO` Step 2 : Assign the oxidation numbers and identify the redox couples. Step 3 : Multiply `As_(2)S_(3)"by "3 and HNO_(3)" by "2.` 3 `As_(2)S_(3)+2HNO_(3)+H_(2)OrarrH_(3)AsO_(4)+H_(2)SO_(4)+NO` Step 4 : Balance all the elements in the EQUATION (As,S and N) except H and O. `3As_(2)S_(3)+2HNO_(3)+H_(2)Orarr6H_(3)AsO_(4)+9H_(2)SO_(4)+2NO` Step 5 : Balance the COMPLETE equation including O & H. `3As_(2)S_(3)+28HNO_(3)+4H_(2)Orarr6H_(3)AsO_(4)+9H_(2)SO_(4)+28NO`

6.	Define oxidation and reduction in terms of electrons
Answer» SOLUTION :OXIDATION INVOLVES loss and REDUCTION involves gain of electron

7.	Define oxidation number?
Answer» Solution :Oxidation number of the element is defined as the RESIDUAL charge which its atom has or appears to have, when all other atoms from the molecule are assumed to be REMOVED as IONS by counting the SHARED electrons with more ELECTRONEGATIVE atoms.

8.	Define oxidation and reduction in terms of oxidation number
Answer» SOLUTION :Oxidation involves INCREASE in O.N while reduction involves decrease in O.N `Sn^(2+)+2HG^(2+)rarrSn^(4+)+Hg_(2)^(2+)` here `Sn^(2+)` gets oxidised to `Sn^(4+)` because its O.N increase from +2 while `HG^(2+)` gets reduced to `Hg_(2)^(2+)` because its O.N decreasefrom + 2 to +1

9.	Define reduction in terms of electronic concepts?
Answer» Solution :OXIDATION is a PROCESS in which loss of ELECTRONS take place. Reduction is a process is which gain of electrons takes place.

10.	What is osmotic pressure?
Answer» Solution :Osmotic PRESSURE can be defined as the pressure that MUST be APPLIED to the solution to stop the INFLUX of the SOLVENT (to stop osmosis) through the semipermeable membrane.

11.	Define orbital? What are the n and I values for 3p_(x) and 4d_(x^2-y^2) electron?
Answer» SOLUTION :(i) Orbtial is a three dimensional space wihich ONE probability of finding the electron is maximum. (ii) For 3 px electron n VALUE = 3, l value = 1 (iii) For `4d_(x^2-y^2)` electron n value = 4, l value = 2.

12.	Define optical isomerism.
Answer» Answer :Compound having same physicaland CHEMICAL property butdiffer only in the rotation of PLANE of the polarized light areknownas optical isomers and the PHENOMENON is KNOWN as optical isomerism.

13.	Define octet rule write its significance and limitations.
Answer» Solution :(A) For Octet rule See Que. No.-9 (B) Significance of octet rule : Based on octet rule the structure of molecule/ion can be represent. Complete octet posses stable state so, correct structure can be separated. It helps in calculation of formal mass of molecule or ion It is useful to understand organic compound and mainly compounds of second periods of predictable. (C) Limitations of the octet rule : Octet rule is not universal. There are three type of exceptions to the octet ruled are as under. (i) Central atom has incomplete octet : The element of1st, 2nd and 3rd group has incomplete octet like H, Li, Be, B , Al ... e.g. LiCl, `BeH_(2), BeF_(2), BH_(3), BCl_(3) , AlCl_(3)` In LiCl octet is not form Li : Cl `BeH_(2) , BeCl_(2) , BeF_(2)` be does not have octet X : Be : X In `BH_(3), BF_(3), BCl_(3),AlCl_(3). ` B and Al does not have octet. `X - underset(X) (B) - X " OR " ` (ii) Odd electron molecules : In certain stable molecule or ion possess add electrons and don.t have octet. e.g. (1) In No, N has 5 `e^(-)` and O has 6 `e^(-)` = 5 + 6 add `e^(-)` still it is stable oxide Not does the octet rule. There N has not octet but has 7 electrons. e.g., (2) N02 Nitrogen dioxide Valence electron : 5 + 6(2) 5 + 12 = 17 (iii) The expanded octet : If atom has more than four bond i.e. 5 or 6, than it has respectively 10 and 12 banding electrons. It is known as expand octet. After third period the elements have 3p, 3s and d orbitals. So for such element expanded octet is formed eg. `PF_(5), SF_(6) and H_(2) SO_(4)`. Total bonding electrons : 8 bond 16 `e^(-)` Total non bonding electrons16 Total 32 `e^(-)` Total electron around = Four O : `(4 xx 4) = 16 ` six bond : `(6 xx 2) = 12 ` (iv) It is clear that octet rule is based upon the chemical INERTNESS of noble gases. However, some noble gases (for example xenon and krypton) also c:omhine with oxygen anct fluorine to form a number of compounds like `XeF_(2), KrF_(2), KrF_(2), XeoF_(2) ` etc. but not followed octer rule. (v) This theory does no account for the shape of molecules. (vi) It does not explain the relative stability of the molecules being totally silent about the ENERGY of a molecule. So, octet rule is not universal but give primary INFORMATION about bond structure which is very useful.

14.	Define Octet rule. Write its significance and limitations.
Answer» Solution :Octet rule: ATOMS of elements combine with each other in order to complete their respective octet so as to acquire the STABLE nearest NOBLE gas configuration. Significance: It helps to explain why different atoms combine with each other to form ionic COMPOUNDS or covalent compounds. Limitations of Octet rule: (i) According to octet rule, atoms take part in chemical eombination to achieve the configuration of nearest noble gas elements. However, some of noble gas elements like Xenon have formed compounds with fluorine and oxygen. For example: `XeF_(2), XeF_(4) XeO_(3)` etc. Therefore, validity of the octet rule has been challenged. (II) This theory does not account for the shapes of molecules.

15.	Define octet rule.
Answer» Solution :Atoms COMBINE to FORM molecules or compounds by transference or sharing of electrons between them so as to have 8 electrons in theiroutermost orbits. This rule is called octet rule.

16.	Define octet rule. Write its significance andlimitation. (Exercise - 4.5) OR What is electronic theory of chemical bonding?
Answer» Solution :OCTET rule: Atoms can combine either by transfer of valence electrons from one atom to another (gaining or losing) or by sharing of valence electrons in ORDER to have an octet in their valence shells. This is KNOWN as octet rule. Kossel and Lewis in 1916 developed an important and Lewis THEORY of chemical combination between atoms known as ELECTRONIC theory of chemical bonding

17.	Define octane number. A sample of gasoline produces the same knocking as mixture containing 35% n-heptane and 65% iso-octane. What is the octane number of the sample ?
Answer» SOLUTION : OCTANE NUMBER = 65

18.	Define - Normality.
Answer» SOLUTION :Normality (N): It is DEFINED as the NUMBER of gram equivalents of SOLUTE in 1 LITRE of the solution. `N=("Number of gram equivalent of solute")/( "Volume of solution (in L)")`.

19.	Define normality.
Answer» Solution :Normality is DEFINED as the NUMBER of gram equivalents of solute present in 1 LITRE of the solution. Normality `(N) = ("Number of gram equivalents of solute")/("Volume of the solution (in L)")`

20.	Define molecular mass.
Answer» SOLUTION :It is defined as "The ratio of the mass of ONE MOLECULE of the GIVEN substances to one-twelfth the mass of an ATOM of `C-12^(@)`.

21.	Define molecular mass of a substance.
Answer» Solution :Molecular MASS of a substance (ELEMENT or COMPOUND) represents the NUMBER of times the molecule of that substance is heavier than 1/`12^(th)` of the mass of an atom of C-12 isotope.Molecular mass = 2 `XX` Vapour density

22.	Define Mole. What is the Value of Avagadro's Number.
Answer» SOLUTION :MASS of a substance which contains AVOGADRO number of PARTICLES. Avogadro number `=6.023xx10^(23)`

23.	Define mole fraction.
Answer» SOLUTION :Mole FRACTION of a component is the ratio of number of moles of the component to the TOTAL number of moles of all components PRESENT in the solution. Mole fraction `= ("Number of moles of component")/("Total number of moles of all components present in the solution")`

24.	Define mole. Calculate number of moles is 49 g H_(2)SO_(4) (Atomic Mass of H=1, O=16,S=32)
Answer» Solution :Mole is the amount of SUBSTANCE that contains as many particles or entities as there are atoms in exactly 12-g of `.^(12)C` isotope. MOLAR mass of `H_(2)SO_(4)=2+32+64=98` No. of MOLES of `H_(2)SO_(4)=49/98=0.5`

25.	Define : (i) Molality of a solution (ii) Isotonic solutions
Answer» Solution :Number of moles of SOLUTE in ONE LITRE of the solution.

26.	Define Molarity. If 5.6 g of KOH is present in 250 ml of the solution, calculate the molarity of the solution.
Answer» Solution : ''The number of moles of SOLUTE dissolved in one litre of the solvent'' is called as Molarity of the solution. Molarity (M) `=("number of moles of solute")/("Volume of the solvent in Litres")` If 5.6 G of KOH is present in 250 ML of the solution Number of moles of KOH `= (5.6 g)/(56 mol^(-1))=0.1` moles Molarity (M) `= ("0.1 moles")/("0.4 Lit")=0.25 "mol Lit"^(-1)` (or) 0.25 M.

27.	Define molarity.
Answer» SOLUTION :MOLARITY is defined as the NUMBER of MOLES of solute present in 1 litre of the solution. Molarity `(M) = ("Number of moles OS solute")/("Volume of the solution(in L)")`

28.	Define molar volume (V_(m))
Answer» SOLUTION :MOLAR volume is the valume OCCUPIED by on mole of substance at a given TEMPERATURE and pressure.

29.	Define - molar heat of sublimation.
Answer» Solution :Molar heat of SUBLIMATION is DEFINED as the CHANGE in enthalpy when one MOLE of a solid is directly converted into the gaseous state at its sublimation TEMPERATURE.

30.	Define molar heat of fusion.
Answer» SOLUTION :The MOLAR heat of fusion is DEFINED as "the change in enthalpy when one mole of a solid SUBSTANCE is converted into the LIQUID state at its melting point".

31.	Define molar heat capacity. Give its unit.
Answer» Solution :Molar heat capacity is defined as "the amount of heat absorbed by ONE mole of a substance in RAISING the temperature by 1 Kelvin". It is DENOTED as `C_m` Unit of Molar heat apacity: SI unit of `C_m` is `JK^(-1) "mol"^(-1)`

32.	Definelatentheatcapacity . Giveitsunit
Answer» Solution :Molar heat CAPACITY is defined as "the amount of heat absorbed by ONE mole of a substance in raising the TEMPERATURE by 1 Kelvin". It is denoted as `C_m` Unit of Molar heat capacity: SI unit of `C_m` is `JK^(-1) mol^(-1)`

33.	Define Molar enthalpy of vapourisation ?
Answer» Solution :AMOUNT of heat REQUIRED to vaporise one mole of a LIQUID at constant temperature and under standard pressure (1 bar) is called molar ENTHALPY of vapourisation.

34.	Define Molar enthalpy of fusion.
Answer» Solution :The enthalpy CHANGE that ACCOMPANIES melting of one mole of a solid substance at its melting POINT is CALLED molar enthalpy of fusion.

35.	Define – molality.
Answer» SOLUTION :Molality (m) : It is defined as the number of MOLES of the SOLUTE PRESENT in 1 kg of the solvent `m = ("Number of moles of solute")/("Mass of the solvent (in kg)")`

36.	Define Molality
Answer» Solution :Molality is defined as the number of MOLES of SOLUTE PRESENT in 1 kg of the solvent. Molality `(m) = ("Number of moles of solute")/("Mass of the solvent (in kg)")`

37.	Define modern periodic law.
Answer» Solution :The modern PERIODIC law STATES that, "the physical and chemical properties of the element are periodic functions of their ATOMIC NUMBERS." Draw the HYDROGEN bonding existing in the following compounds.

38.	Define mixture and its types.
Answer» Solution :Many of the substances present around you are mixtures. Example: Suger solution, air, tea etc. A mixture contains TWO or more substances present in it are called its components. A mixture MAY be two types : (i) Homogeneous (ii) Heterogeneous Homogeneous mixture : The components completely mix with with each other and its COMPOSITION is UNIFORM throughout. e.g. Sugar solution, and air Heterogeneous mixtures : This composition is not uniform throughout and sometimes the different components can be observed. e.g. The mixtures of salt and sugar, grains and PULES along with some dirt( often stone) pieces. The components of a mixture can be separated by using physical methods such as simple hand picking, filtration, crystallisation, distillation etc.

39.	Define melting point (or) freezing point of the substance
Answer» SOLUTION :The temperature at which the solid and liquid phases of a SUBSTANCE are at equilibrium is called the MELTING POINT or FREEZING point of substance.

40.	Define metallic hydride or interstitial hydrides.
Answer» Solution :These are the hydrides of transition metals which are non-stoichiometric in NATURE. The small hydrogen atoms occupy the INTERSTITIAL space th metal atoms in their CRYSTALS. Ex : `TiH_(1-70),ZrH_(1-9),LaH_(3)" etc., "`

41.	Define matter. What are the types of matter?
Answer» SOLUTION :A MATTER is ANYTHING which has MASS and occupies space. Matters exist in all three STATES such as solid, liquid and gas

42.	Define Mass percentage?
Answer» SOLUTION :Mass PERCENTAGE is defined as the ratio of the mass of the SOLUTE in g to the mass of solution in g multiplied by 100. Mass PERCANTAGE `= ("Mass of the solute(in g)")/(Mass of solution (in g)") xx 100`

43.	Define mass by volume percentage.
Answer» Solution :It is defined as the ratio of the MASS of the SOLUTE in g to the volume of the solution in ml MULTIPLIED by 100. Mass by volume `=("Mass of the solute (in g)")/(" Volume of the solution (in mL)") XX 100`

44.	Define Mass and Weight.
Answer» Solution :Mass of a SUBSTANCE is the amount of matter present in it, while wight is the force exerted by gravity on an object. The mass of a substance is constant whereas its weight may vary from one place to another due to the CHANGE in gravity. The mass of a substance can be determined very accurately in the laboratory by USING an analytical balance. ( see figure) The SI unit of mass is kilogram. Its fraction gram `(1kg=1000g)`, is used to laboratories due to the smaller amounts of chemicals used in chemical reactions. Volume has the units of `("length")^(3)`. So in SI system, volume has units of `m^(3)`. But again, in chemistry laboratories, smaller volumes are used . Hence, volume is often denoted in `cm^(3)` or `dm^(3)` units. A common unit, litre (L) which is not an SI unit, is used for measurement of volume of liquids. `1 L = 1000 kL, 1000 cm^(3) = 1 dm^(3)`. To visualise these relations see figure: In the laboratory, volume of liquids or solutions can be measured by graduated cylinder, burette, pipette etc. A volumetric flask is used to prepare a known volume of a solution. These MEASURING devices are SHOWN in figure.

45.	Define lonization enthalpy.
Answer» Solution :The energy required to remove the most loosely held ELECTRON from an isolated gaseous ATOM is called as IONIZATION energy(i.e) `"Atom"_(("g"))+"Energy"to"Positive Ion"_(("g"))DIV"Electron"` `"Li"_((g))+520" kJ mol"^(-1)to"Li"_((g))^(+)+e^(-)`

46.	Define ionic radius.
Answer» Solution :The ionic radius of an ION is the distance between the CENTRE of the ion and the outermost POINT of its ELECTRON cloud.

47.	Define lonization energy. Give its unit.
Answer» Solution :The energy required to remove the most loosely held electron from an isolated gaseous atom is CALLED IONIZATION energy. `M_((G))+" energy to "M_((g))^(+) + "electron"` The unit of ionization energy is KJ `mol E^(-1)`

48.	Define Lewis acid. Give one example for Lewis acid.
Answer» ANSWER :Acid is a SUBSTANCE which ACCEPTS electrons. Eg. `BF_(3)`

49.	Define - Le-Chatelier principle .
Answer» Solution :. It states that "If a systym at EQUILIBRIUM is disturbed, then the system SHIFTS itself.in a direction that NULLIFIES the effect of that DISTURBANCE

50.	DefineLaw of Conservation of Mass.
Answer» Solution :This law was put FORTH by Antoine LAVOISIER in 1789. He PERFORMED careful experimental studies for COMBUSTION reactionsfor reaching to the above conclusion. This law formed the basis for several later developments in chemistry. Infact, this was the result of exact measurement of MASSES of reactants and products, and carefully planned experiments performed by Lavoisier