Explore topic-wise InterviewSolutions in .

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.

5401.

How does the electronic configuration of an atom relate to its position in the modern Periodic Table?

Answer»

SOLUTION :The group number of elements having UPTO two valence electrons is EQUAL to the number of valenceelectrons. The group number of elements having more than two valence electrons is equal to the number of valence electrons PLUS 10. For example,
Discussion
5402.

How does the electronic configuration of an atom related to its position in the modern periodic table ?

Answer»

SOLUTION :In the modern periodic table, atoms with similar electronic configurations are placed in the same COLUMN. In a group, the number of valence electrons remains the same. ELEMENTS ACROSS a PERIOD show an increase in the nmnber of valence .electrons.
Discussion
5403.

How does the concentration of hydronium ions change during dilution of an acid?

Answer»

SOLUTION :Dilution of an acid decreases the CONCENTRATION of hydronium ions PER UNIT VOLUME
Discussion
5404.

How does the atomic size vary as you go down a group ?

Answer»

Solution :As we GO down a group, the atomic SIZE increases GRADUALLY.
Discussion
5405.

How does the atomic radius change as you go from left to right in a period ?

Answer»

SOLUTION :The ATOMIC RADIUS DECREASES as we go left to right in a PERIOD.
Discussion
5406.

How does the atomic radius change as we go : (i) from left to right across a period (ii) down a group in the periodic table ?

Answer»

Solution :On going :
(i) From LEFT to right across a period, atomic radius decreases as ONE proton and one electron are added continuously, therefore effective nuclear charge increases.
(ii) Down a group in the PERIODIC table, atomic radius increases because number of SHELLS goes on INCREASING, therefore distance between nucleus and valence shell increases.
Discussion
5407.

How does the acidic character vary among the trihalides of boron ? Give a reason in suport of your answer

Answer»

Solution :(i) comparison of electronegativities of halogens attached to boron in various trihalides
(ii) reason for the trihalides of boron to act as an acid
(iii) comparison of valence electronic configuration of FLUORINE, chlorine, bromine, IDOINE with that of boron
(iv) orbitals in which the lone pairs of electrons of halogens are present
(V) identification of VACANT orbital of boron
(vi) comparison of energy of vacant orbital of boron with the orbitals containing lone pairs of electrons in halogens
(viii) relation between the tendency of formation of the above kind of bond and availability of vacant orbital of boron for accepting the lone pairs of electrons from other species
(ix) comparison of acidic characters of trihalides of boron according to Lewis CONCEPT
Discussion
5408.

How does temperature change when quicklime is treated with water ?

Answer»

SOLUTION :TEMPERATURE INCREASES.
Discussion
5409.

How does pH play an important role in everyday life?

Answer»

Solution :(i)The pH of blood is almost 7.4 Any increase in this value leads to diseases.
(ii)CITRUS fruits require slightly alkaline soil,while rice requires acidix soil and surgarcane requires neutral soil.
(iii)If pH of rain water becomes less than 7,it becomes acid rain which is harmful in day-to-daylife.
(iv) pH CHANGES cause tooth fecay.
(v)During INDIGESTION the stomatch produces too much acid this causes pain and IRRITATION.
Discussion
5410.

How does pH play ann important role in everyday life?

Answer»

Solution :pH in Ourdigestivesyetm:
(I )ourstomachproduceshydrocloricacidwhichhelpsin thediagestionof foodwithoutharmingthe stomach.
(II )Duringindigestion, if thestomachproducestoo muchacidand thiscausespainandirritation .
(iii ) pHof thestomachfluidis approximately2.0.
ph of thesaliva :
(i) pHof thesaliva normallyrangesbetween6.5 to 7.5 .
(ii)Whenthe pH of themouthsalivafallsbelow 5.5 , theenamelgetsweathered .
(iii )Toothpastes, WHICHARE generallybasicareusedfor cleaningtheteeth that canneutralisethe excess acidand preventtoothdecary.
(ii )Citrusfruitsrequireslightly alkalinesoil , whilericerequiresacidicsoilandsugarcanerequiresneutralsoil .
pHof rain water:
(i)THe pHof rainwaterisapproximately7,whichmeansthat it is neutraland alsorepresentsitshighpurity .
(ii )If theatmosphericairis pollutedwithoxidegasesof sulphurand NITROGEN, theygetdissolvedin therainwaterand makeitspHlessthan 7.
(iii )IF thepHof rainwateris LESSTHAN 7,thenitis calledacidrain.
(iv )Whenacidrainflowsintotheriversitjowers thepHof theriverin suchriversbecomesdifficult .
Discussion
5411.

(i)Howdoes overload and short-circuit occur in an electric circuit ? Explain . What is the function of fuse during this situation ?(ii)Mention two properties of magnetic field lines .

Answer»

Solution :Overloading can oceur when the live wire and the neutral wire come into direct contact.
This occurs when the insulation ot wires is damaged or there is a fauli in the applianee.
u such a situation, the current in the cireuit abruptly increases.
The heating that takes place in thc luse melts it to BREAK the electrie CIRCUIT and prevents the electric appliances trom possible damage.
(ii) No TWO ficld lines are found to cross each otiher.
he density of the MAGNETIC field lines are more in their polcs.
The nagnetic ficld lines emerge from north pole and merge at south pole.
nside the nagnet, the direction of field lines is from its south pole to its north pole.
Thus ihe magnetie ficld lines are closed curves.
Discussion
5412.

How does metallic character of elements vary on moving from : (i) Left to right in a period ? (ii) From top to bottom in a group ? Give reasons for your answers.

Answer»

SOLUTION :(i) Decreases, DUE to DECREASE in tendency to lose ELECTRONS.
Increases, due to INCREASE in tendency to lose electrons.
Discussion
5413.

How does magnesium connected by a wire to buried iron pepeline protect if from corrosion ?

Answer»

Solution :Magnesium preferntically gets reduced to `Mg^(+2)` ions over iron. Therefore, iron does not PRODUCE `FE^(+2)` ions. Due to this reason, iron is protected from CORROSION when it is connected to magnesium
Discussion
5414.

How does metallic character of a metal depend on the size of atom?

Answer»

Solution :The METALLIC character of a METAL increases with INCREASE in the size of its atom.
Discussion
5415.

How does galvanisation of iron protect iron from rusting even when protective zinc coating is partially worn away ?

Answer»

Solution :(i) Relative reactivity of ZINC and IRON. ltBrgt (ii) Change undergone by iron during rusting.
(III) Comparison of oxidation potentials of zinc and iron.
(iv) Mode of prevention of rusting by zinc if the COATING is partially WORN away.
Discussion
5416.

How does electronic configuration of atoms change within a period, with increase in atomic number ?

Answer»

Solution :On moving ACROSS a PERIOD from left to right , the atomic number of the elements, increases. Therefore, the number of electrons in the VALENCE shell increases from 1 to 8 i.e the first element in the GIVEN period will have one electron in its valence shell and the last element in the same period will have eight eletrons.
Discussion
5417.

How does dilution affect the conductivity of strong electrolytes and weak electrolytes ?

Answer»

Solution :In case of strong electrolytes, when the concentration of the solution is high, the number of solvent molecules is few and the oppositely charged ions are CLOSED to each other. This results in strong electrostatic forces of ATTRACTION between the ions and lesser mobility of the ions. This accounts for increase in conductivity with DILUTION. In case of weak electrolytes, degree of DISSOCIATION INCREASES with dilution
Discussion
5418.

How does de Broglie's theory support Bohr's theory?

Answer»

SOLUTION :According to Bohr's atomic theory, electrons revolve AROUND the nucleus in a circular path with a FIXED angular momentum. According to de BROGLIE, electron has a dual nature - particle nature and wave nature. The nature of the wave should be bke a stationary wave if the path of the electron is circular. The circumference of the circular path of the electron should be an integral multiple of the wavelength of the wave associated with the electron since the wave is a stationary wave. The ENERGY of the wave associated with the electron moving in a particular orbit is quantised because the wavelength of it is fixed for that particular orbit
Discussion
5419.

How does carbon attain a stable electronic configuration?

Answer»

SOLUTION :Carbon ATTAINS stable ELECTRONIC CONFIGURATION by SHARING its four electrons with other atoms.
Discussion
5420.

How does aqueous and acidified CuSO_(4) dissociate on the passage of current ? Also write the electrode reactions at the respective electrodes

Answer»

Solution :Aqueous acidified copper sulphate DISSOCIATES as shown below.
`CuSO_(4) rarr Cu^(2+) + SO_(4)^(-2) "," H_(2)O rarr H^(+) + OH^(-) "," H_(2) SO_(4) rarr 2H^(+) + SO_(4)^(2-)`
REACTION at cathode: Copper gets discharged at the cathode because of lower DISCHARGE potential than that of hydrogen.
`Cu^(2+) + 2e^(-) rarr Cu`
Reaction at anode
(i) If anode is platinum or graphite (inactive anode) `OH^(-)` is discharged at the anode because its discharge potential is lower than that of `SO_(4)^(2-)` ion. `4OH^(-) rarr 2H_(2)O + O_(2) + 4e^(-)`
(ii) If the anode is copper itself (active anode)
`Cu - 2e^(-) rarr Cu^(2+)`
No product is formed at anode.
Discussion
5421.

How does Aluminium react with caustic soda > Give equation.

Answer»

SOLUTION : Aluminium reacts with caustic SODA to give sodium META aluminate with the liberate of `H_(2)` gas `2Al+2NaOH + 2H_(2)ORightarrow2NaAlO_(2) + 3H_(2)`
Sodium meta aluminate
Discussion
5422.

How does a strong acid differ from a concentrated acid?

Answer»

SOLUTION :The STRENGTH of an ACID depends upon its dissociation power where as concentration depends on WATER content in the acid.
Discussion
5423.

How does a solenoidbehave like a magnet ? Can you determinethe north and south polesof a current-carrying solenoid with the help of a bar magnet ? Explain.

Answer»

Solution :When electric current flows through a solenoid, magnetic field is set up around the solenoid. The pattern of the magnetic field is same as that of the magnetic field of a bar magnet. One end of the solenoid BEHAVES as NORTH pole and the other end of the solenoid behaves as SOUTH pole. To determine the north and south poles of a current carrying solenoid with the help of a bar magnet, suspend it with a strong thread. Now bring the north pole of a bar magnet TOWARDS one end of the solenoic. If the solenoid ATTRACTS towards the magnet then the face of the solenoid is south pole. If the bar magnet moves away from the solenoid, then the face of the solenoid is the north pole.
Discussion
5424.

How does a soap behave in the presence of Ca^(2+) and Mg^(2+) ions in solution ?

Answer»

Solution :Soap is sodium or POTASSIUM salt of fatty acid which CONTAINS a large chain of CARBON atoms. Soap interacts with the `Ca^(2+) and Mg^(2+)` ions of produce insoluble salts of calcium or magnesium which separat from the solution as SCUM :
` underset("soap")2Na(Ft) + Ca^(2+) to underset("scum") Ca(Ft)_(2) darr + 2Na^(+)`
Discussion
5425.

How does a soap solution behave with red litmus paper ?

Answer»

SOLUTION :SOAP solution is BASIC in nature. So , it MAKES a RED litmus paper blue.
Discussion
5426.

How does a chemical equation makes a reaction more informative ?

Answer»

Solution :For making a chemical EQUATION more informative -
(1) The physical states of the REACTANTS and PRODUCTS are REPRESENTED by symbols (g) for gas, (1) for liquid, (s) for solid and (aq) for aqueous solution.
(2) Specific conditions like temperature, pressure, catalyst are shown above `//` below the arrow in the equation.
Discussion
5427.

How do you trace the magnetic field lines around a bar magnet using compass needle ? Explain. Write the properties of magnetic field Lines.

Answer»

Solution :(a) Place the bar magnet on a sheet of white paper fixed on a drawing board. Mark the boundary of the magnet.
(b) Place the magnetic compass near the north pole of the given magnet.
(c) Mark the position of two ends of the needle. Now move the needle to a new position such that its south pole occupies the position previously occupied by its north pole .
(d) In this way PROCEED step by step till you reach the south pole of the given magnet.
(e) Join the points marked on the paper by a smooth curve. This curve represents a field line. Repeal the above steps for new POSITIONS of compass needle.

Properties of magentic filed lines. :
(i) Two magnetic field lines never intersect each other.
(ii) Outside the magnet, the magnetic field lines are DIRECTED from North pole of magnet towards South pole.
(iii) The magnetic field lines at any one POINT gives the DIRECTION of magnetic field at that point.
Discussion
5428.

How would the tendency to gain electrons change as you go down a group?

Answer»

Solution :The tendency of lose ELECTRONS (electro POSITIVITY) INCREASES as we go down a GROUP.
Discussion
5429.

How do you think the tendency to lose electrons changes in a group ?

Answer»

Solution :As we MOVE from top to BOTTOM in a GROUP, the TENDENCY to lose electrons increases.
Discussion
5430.

How do you identify the following cations in their aqueous solutions by using caustic soda solution ? (i) Fe^(+2) (ii) Zn^(+2) (iii) Al^(+3)

Answer»

Solution :(i) `FE^(+2)` gives light green precipitate of ferrous hydroxide `(Fe(OH)_(2))`
(ii) `Zn^(+2)` gives white precipitate of zinc hydroxide `(Zn(OH)_(2))`
(III) `Al^(+3)` gives white gelationous precipitate of ALUMINIUM hydroxide `(Al(OH)_(3))`
Discussion
5431.

How do you differentiate between saturated and unsaturated hydrocarbons with the help of combustion reactions?

Answer»

Solution :Saturated hydrocarbons BURN with a blue non-SOOTY flame but unsaturated hydrocarbons burn with a yellow sooty flame.
Discussion
5432.

How do you classify elements into metals and non metals on the basis of their electronic configuration? Choose metal and non metal out of the following? _11^23A,_9^19B,_12^24C,_15^51D,_17^35E

Answer»

Solution :Elements which contain 1 to 3 electrons in their outermost SHELL are METALS.
Elements containing 4 to 7 electrons in their valence shell are NON metals.
Electronic configurations:
`_11^23A(Z=11)=2,8,1_9^19B(Z=9)=2,7`
`_12^24C(Z=12)2,8,2 _15^31D(Z=15)=2,8,5`
`_17^35 E (Z=17)=2,8,7`
HEnce A and C are metals WHEREAS, B D and E are non metals.
Discussion
5433.

How do you calculate valency of an element from its electronic configuration?

Answer»

Solution :(i) Electronic configuration tells about the valence ELECTRONS. If the NUMBER of valence electrons are 1, 2 or 3, then such elements will donate 1, 2 or 3 electrons. Their valency is also 1, 2 or 3 RESPECTIVELY.
(ii) If an ELEMENT has 4 valence electrons , it shares all 4 electrons, so the valency is 4 . If the number of valence electrons are 5, 6 or 7 electrons, then such elements accept 3 , 2 or 1 electrons respectively, thus their valency is 3, 2 or 1 .
(iii) When the valence electrons ar e 2 (for only one shell) or 8 then it is a stable electronic configuration. Thus, the valency is zero.
Discussion
5434.

How do you calculate the valency of an element from its electronic configuration?

Answer»

SOLUTION :The valency of an ELEMENT is DETERMINED by the number of valence electrons present in theoutermost shell of its atom. The number of electrons LOST or gained (or shared) by one atom of anelement to achieve the nearest inert gas electron configuration, gives us the valency of the element.
Discussion
5435.

How do you calculate the valency of an element from its electronic configuration ?

Answer»

Solution :The valency of an ELEMENT is determined by the number of valence ELECTRONS present in the outermost shell of the atom.
For elements of GROUP 1, 2, 13 and 14, the valency is equal to the number of valence electrons and for elements of group 15, 16, 17 and 18, the valency is equal to 8 minus number of valence electrons.
Discussion
5436.

How do you bring about the following conversions: a] Ethanol to ethene. b] Ethanol to ethanoic acid.

Answer»

SOLUTION :
Discussion
5437.

How do you balance the chemical equation ? Explain it stepwise with suitable illustration.

Answer»

Solution :Consider the following equation:
`Fe+H_(2)O to Fe_(2)O_(4)+H_(2)`
Steps for balancing the equation are as follows:
Step 1: To balance a chemical equation, first place each formula in the box. Do not change anything inside the box during balancing the equation.

Step 2: List the number of atoms of given elements present in the unbalanced equation (1.1).

Step 3: Select the COMPOUND having maximum number of atoms and balance the elements which have higher number of atoms.
Here first balancing the number of oxygen atoms of `FeO_(4)`

Here, it must be remembered that during balancing the atoms, do not alter the chemical formulae. For example, to balance the oxygen atoms, place co-efficient 4 before `H_(2)O` but do not write `H_(2)O_(4)`or `(H_(2)O)_(4)`. Hence, equation (1.1) can be written as -

Step 4: H and Fe atoms are still not balanced in equation (1.2). Now balance the H atoms. To equalise the number of H atoms, multiply the number of molecules of `H_(2)`by 4 in right side.

Step 5: Fe atoms are still not balanced in equation (1.3). To equalise the number of Fe atoms, Multiply the Fe by 3 on left side. Hence, equation (1.3) will be as

step 6:Remove BOXES
`3Fe+ 4H_(2)O to Fe_(3)O_(4)+2H_(2)` (Balanced equation) ..(1.4)
The number of atoms on both sides of equation (1.4) are equal. This is called balanced chemical equation. This METHOD of balancing the chemical equations is called hit-and-trial method. Step 7: Physical states of the substances are mentioned along with their symbols to make the chemical equation more informative. Symbols (g) for gases. (1) for liquids, (s) for SOLIDS and (aq) for aqueous solution are written.
Thus, equation (1.4) will be written as -
`3Fe(s) + 4H_(2)O(g)toFe_(3)O_(4)(s) + 4H_(2)(g)`
Sometime, the reaction conditions such as temperature, pressure, catalyst, if any, are represented above and / or below the arrow.
For example `CO(g)+3H_(2)(g) overset(340atm)to CH_(3)OH(I)+6CO_(2)(g)+6H_(2)O(I) underset("Chlorophyll")overset("Sunlight")to C_(6)H_(12)O_(6)(aq)+6O_(2)(g)`
Discussion
5438.

How do you account for the acidic nature of 10^(-8) M nitric acid ? Justify by mathematical calculation (log 1.1 = 0.041)

Answer»

Solution :(i) pH range of acidic solution
(ii) number of hydrogen ions furnished by NITRIC acid, PRESENT in the solution
(iii) DETERMINATION of concentration of the hydrogen ions furnished by nitric acid
(IV) influence of the concentration of hydrogen ions furnished by the acid on the DEGREE of dissociation of water.
(v) concentration of hydrogen ions furnished by water
(vi) total concentration of hydrogen ions present in the solution.
(vii) calculation of pH
Discussion
5439.

How do we know whether a given element is a non-metal if we know its electronic configuration ?

Answer»

SOLUTION : If there are four or more than four ELECTRONS in the VALENCE CELL of the given element, it is a non-metal
Discussion
5440.

How do we come to know that a chemical reaction has taken place?

Answer»

Solution :The presence of any of the following changes helps us to determine that a chemical REACTION has taken place.
(i) FORMATION of new substance(s) (II) Change in STATE
(iii) Change in colour (iv) Change in temperature
(v) Formation of a precipitate (vi) Evolution of a gas
For example, if on mixing two substances a gas is evolved, then we can say that a chemical reaction has taken place.
Discussion
5441.

How do transition elements differ from other elements?

Answer»

Solution :Transition ELEMENTS have VARIABLE VALENCY. Their valency can.t be predicted on the BASIS of any law.
Discussion
5442.

How do the following traits change in a period from left to right in the periodic table : (a) Atomic size (b) Valency (c) Metallic character.

Answer»

Solution :(a) ATOMIC size decreases as we move from left to right in the Periodic Table. This is because the electrons are added to the same shell. Because of increased ATTRACTION between the nucleus and the electrons, atomic size decreases.
(b) Valency increases as we move from left to right to some point after which it decreases. Valency depends upon the number of electrons which an atom can LOSE, gain or share with other atoms.
(c) Metallic character decreases as we move from left to right in the Periodic Table. Metallic character means tendency to lose electrons. On MOVING from left to right, the force of attraction between the nucleus and valence electrons increases. THEREFORE elements have smaller and smaller tendency to lose electrons.
Discussion
5443.

How do the following change ? (a) Number of shells of elements as we go down a group. (b) Numberofvalenceelectronsofelementsonmoving from, left to right in a period. (c ) Atomic radius in moving from left to right along a period. (d) Atomic size down a group.

Answer»

Solution :(a) Numberofshellsofelementsgoesonincreasingdownthe group.
(b) Numberofvalenceelectronsofelementsgoesonincreasing on moving from left to right in a period eg. Lithium has 1, berylliumhas2,boronhas3,carbonhas4,nitrogenhas5, oxygen has 6, fluorine has 7 and NEON has 8 VALENCE electrons.
(c ) Atomic RADIUS goes on decreasing in moving from left to right along a period.
(d) atomic SIZE goes on INCREASING down a group.
Discussion
5444.

How do Mendel's experiments show that traits are inherited independently?

Answer»

Solution :Mendel crossed pure BREEDING tall plants having round seeds with pure breeding shorts plant with wrinkled seeds to prevent SPECIATION. In their case, plants having wrinkled seeds. The plants of `F_1` - Yielded plants with character of tall round seeded, 3 tall wrinkled seeded, 3 short round seeded and one short wrinkled seeded. Tall wrinkled seeded and COMBINATION which can develop only when the traits are INHERITED independently.
Discussion
5445.

How do detergentscause waterpollutions ? Suggest remedial measures to preventthis pollution .

Answer»

Solution :Some detergentshaving a branched hydrocarbon CHAIN are not fully BIODEGRADABLE by micro-organism preventin WATER . So, they cause water pollution .
REMEDIAL measures :
Replacingthe detergentslike branchedhydro carbon chains with liner hydro carbon chainswhich are biodegradable .
Discussion
5446.

How do detergents cause water pollution? Suggest remedial measures to prevent this pollution?

Answer»

Solution :Some detergents having a BRANCHED HYDROCARBON CHAIN are not fully biodegradable by micro-organisms present in water. So, they cause water pollution.
They have straight hydrocarbon chains, in biodegradable detergents, which can be EASILY degraded by bacteria.
Discussion
5447.

How do decomposition reactions differe from combination reactions :

Answer»

Solution :In a decomposition reaction , a compound is BROKEN down into TWO or more simpler substances, whereas in a combination reaction, two or more substance combine to produce a SINGLE substance.
Discussion
5448.

How do atoms exist ?

Answer»

SOLUTION :Atoms of most of the elements are CHEMICALLY very reactive and do not exist in the free State (as SINGLE atoms). Atoms USUALLY exist in TWO ways-(a)In the form of molecules (b) In the form of ions
Discussion
5449.

How do alkanes and alkenes with same number of C atoms differ with respect to theNumber of H atoms

Answer»

SOLUTION : An ALKANE CONTAINS two more H atoms than the CORRESPONDING alkene.
Discussion
5450.

How do alkanes and alkenes with same number of C atoms differ with respect to the Nature of bonds between carbon atoms

Answer»

Solution :In alkane, C to C bond is SINGLE, WHEREAS an alkene INVOLVES C to C DOUBLE bond.
Discussion