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.

Ina science fair , a student took two test tubes labelled A and B filled with copper sulphate solution, then he put magnesium ribbon in test tube A silver foil in tube B.Predict the observation and justify.

Answer»

SOLUTION :`{:("A","B"),(CuSO_(4),CuSO_(4)),(+,+),(Mg,Ag),(darr,darr),(MgSO_(4)+Cu,"No reaction"):}`
The blue coloured `CuSO_(4)`solution in test tube 'A'disappears and thus COLOURLESS sloution of`MgSO_(4)`is formed .thisis due to higher reactivity of Mg than Cu . Hence Mg can DISPLACE Cu from `CuSO_(4)`solution and hence blue coloured `CuSO_(4)` SLOWLY turns colourless .Ag being less reactive than Cu, cannot displace Cufrom`CuSO_(4)` and hence the solution remains blue.
Discussion
2.

In a ________ properties of the constituents are retained.

Answer»


SOLUTION :MIXTURE
In a mixture the PROPERTIES of its CONSTITUENTS are RETAINED.
Discussion
3.

In a double decomposition reaction , one of the products is insoluble . Whattypeof reaction is that ?

Answer»

SOLUTION :It is CALLED PRECIPITATION REACTION.
Discussion
4.

In a chemistry laboratory, aresearch scholar while conducting an experiment , observed at a certain step, that a yellow coloured gas (X) was released and it has been found to bepoisonous. This was later made to react with a highly reactive metal (Y). A new compound (Z)wasformed which is used for preservation of fish, meat and pickles. The professor asked him toidentify X, Y and Z.

Answer»

SOLUTION :A greenish YELLOW POISONOUS gas 'X' is CHLORINE. Onreaction with a metal, sodium (highly REACTIVE metals) chlorine gas forms sodium chloride which is used for preservation of fish, meats and pickles. So 'Z' is sodium chloride, 'X' is chlorine gas and Y is sodium metal.
Discussion
5.

Ina chemical laboratory , a student broke the thermometer while performing an experiment . Immediately, the mercury which was spilled over was removedby the lab - incharge by sprinkling sulphur on it . Theteacher asked the students to predict the type of change / reaction associated with the above process. Explain with apporpriate reasons.

Answer»

Solution :When mercury gets spilled on the floor or any surface , it can be collected by SPRINKLING sulphur powder because HG reacts with S to form HGS.
`Hg+StoHgS`
It is element - element combination that is SYNTHESIS reaction.
Discussion
6.

If theformula of respective chlorides of X andY are XCl_(3) andYcl_(4) respectively , then the valencies of X and Y are

Answer»

3 and 2
3 and 4
1 and 1
1 and 4

Solution :`XCl_(3),YCl_(40) to`the VALENCY of X and Y are 3 and 4.
Discussion
7.

If the formula of metal sulphite of a metal M is MSO_(3) ,give the formulae of its(a)phosphate(b)hydrogen phosphate (c ) chloride

Answer»

Solution :In`MSO_(3),`the valency of sulphite is 2. HENCE the valency of M is also 2.
Discussion
8.

If the formula of a metal ion is M^(+2)then the formula of its dihydrogen phosphate is

Answer»

`M_(2)(PO_(4))_(3)`
`MHPO_(4)`
`M(H_(2)PO_(4))_(2)`
`M_(2)HPO_(4)`

SOLUTION :VALENCY of metal is 2.
Discussion
9.

If the formula of a metal nitrite is M(NO_(2))_(2.), then the formula of its dihydrogen phosphate is

Answer»

`M_(2)(PO_(4))_(3)`
`MHPO_(4)`
`M(H_(2)PO_(4))_(2)`
`M_(2)HPO_(4)`

Solution :`M(NO_(2))_(2)`, HENCE valency of metal is 2.
Discussion
10.

If overline(X) ion has 10 neutrons and 9 protons , then the electronic configuration of the atom of the element x is

Answer»

1 ,8 ,1
2 , 1
2 , 8
2 ,8,8

Solution :`X^(-)` possess 9 protons (Z), 10 NEUTRONS and 10 electrons
`Xoverset(+l e^(-1))toX^(-1)`
(9 electrons)""(10 electrons)
Therefore , the electronic CONFIGURATION of an atom is 2 , 7
Discussion
11.

If a uninegative ion has 10 neutrons and9 protons, electronicconfiguration of the atom ofthe element is

Answer»

2,8, 1
2, 7
2, 8
2,8 , 8

Solution : `X^(-) = 9` PROTONS (Z)
10 neutrons
10 electrons
`Xoverset(+1e^(-))toX^(-1)`(9 electrons)""(10 electrons)
Therefore , the electronic configuration of an atom is 2 , 7
Discussion
12.

If a solidnon- metal 'X'forms oxide of type X2O5 , the valency of X is

Answer»

3
5
6
4

Solution :`OVERSET(+5)(X_(2))overset(-2)(X_(5))`
Valency of NON - METAL is 5.
Discussion
13.

If a solid non-metal X forms oxide of type X_(2)O_(5),then the formula of its corresponding chloride is ___________ .

Answer»

`XCl_(3)`
`XCl_(5)`
`X_(2)Cl_(5)`
`X_(3)Cl_(2)`

Solution :`+5-X_(2)O_(5)`
SINCE the valency of chloride ION is 1, the FORMULA of the aobve chloridewould be
Discussion
14.

If a nonmetal forms only two oxides and one oxide on hydrolysis gives an acid, then the non-metal could be

Answer»

sulphur
carbon
phosphorus
nitrogen

Solution :Carbon FORMS TWO oxides. `CO_(2)` on hydrolysis gives CARBONIC acid and CO is neutral. Carbon is the non-metal.
`CO_(2) + H_(2)O rarr H_(2)CO_(3)`
Discussion
15.

If a dipositve ion of an element 'X' consists of 12 protins and 12 neutrons and another dipositve ion of an element 'Y' consists of 18 electrons and twice the number of electrons of dipositive ion X is the number of neutrons of Y . Thenthe mass numbers wouldbe in the ratio of

Answer»

` 1 : 2 `
`3:5`
`12:19`
`2 : 3`

Solution :In`X^(+2)`, Number of protons = 12 (Z)
NEUTRONS = 12
Number of electrons = 10
Mass number (A) = 12 + 12 = 24
In `Y^(+2)` electrons are there.
In Y 20 electrons or 20 protons (Z) are there .
Mass number (A) = 20 +20 = 40
`:.`Ratio of mass number`=A_(x) "" : "" A_(y)`
`{:(24,:,40),(3,:,5):}`
Discussion
16.

Ifadispositve ion of an element 'X' consists of 12 protons and 12 neutrons and another dipositve ion of an element 'Y' consistsof 18 electrons and twice the number of electrons of dipostive ion X is the number of neutrons of Y. Then the mass number would be in the ratio of

Answer»

`1:2`
` 3:5`
`12:19`
`2:3`

Solution :`X^(+2)=`No . Of protons= 12 (Z)
NEUTRONS= 12
No . Of electrons= 10
A= 12+ 12=24
`Y^(+2)` =18 electrons.
Y = 20electrons or 20 protons (Z)
A=20+20= 40
`A_(X):A_(Y)`
`24:40`
`3:5`
Discussion
17.

Identify true statement among the following.

Answer»

The CONSTITUENTS of both compound and mixture can be separated by PHYSICAL methods only.
The constituents of both compound and mixture can be separated by CHEMICAL methods only.
The constituents of compounds and mixture can be separated by chemical METHOD and physical methods respectively.
The constituents of compounds and mixture can be separated by physical methods and chemical methods respectively.

Solution :The constituents of a compound do not retain their properties. Hence they can be separated by chemical methods. The constituents of a mixture retain their properties. Hence they can be separated by physical methods.
Discussion
18.

Identify the wrong statement among the following.

Answer»

MOLECULES of SOLIDS prossesss only vibratory motion.
Solids are incompressible.
Solids have only one free surface.
Gases are HIGHLY diffusible.

Solution :Solids have many free surfaces because the molecules have only vibratory motion and hance are fixed.
Discussion
19.

Identify the true statement among the following.

Answer»

Both COMPOUNDS and mixtures are HOMOGENEOUS.
Both compounds and mixtures are homogeneous.
Compounds are homogeneous and mixtures are heterogeneous.
Compounds are homogeneous and mixtures can be homogeneous or heterogeneous.

Solution :Compounds are homogeneous while MIXTURE can be EITHER homogeneous or heterogeneous
Discussion
20.

Identify the substance which continue to burn in an atmosphere ofN_(2).

Answer»

Fe
Mg
Cu
W

Solution :MAGNESIUM CATCHES FIRE when its reacts with oxygen and continues to continues to burn in an atmosphere of `N_(2)`.
Discussion
21.

Identify the substance which doesn't continue to burn in an atmosphere of H_(2).

Answer»

Na
Mg
K
W

Solution :Since sodium, magnesiumand potassium are active metals, they CATCH FIRE when they REACT with oxygen and continue to in an ATMOSPHERE of `N_(2)`, while tungsten (W) which burns in presence of oxygen, doesn't continue to burn in an inert atmosphere of `N_(2)`.
Discussion
22.

Identify the strong acid and weak base among the following respectively.

Answer»

HCI and KOH
`Ca(OH)_(2) "and" Al(OH)_(3)`
`HNO_(3) "and" Al(OH)_(3)`
`H_(2)CO_(3) "and" NH_(4)OH`

SOLUTION :`HNO_(3)` is STRONG acid and `A1(OH)_(3)` is weak base.
Discussion
23.

Identify the soft metal among the following

Answer»

IRON
Aluminium
Magnesium
POTASSIUM

Solution :Potassium is a SOFT METAL.
Discussion
24.

Identify the set of pure and impure water among the following

Answer»

RAIN water, sea water
Rain water, distilled water
Sea water, RIVER water
River water, GROUND water

Solution :Rain water and sea water are PURE and impure water respectively.
Discussion
25.

Identify the salt which does not contain either replaceable hydrogen ions or hydroxyl ions.

Answer»

Magnesium hydroxy chloride
Sodium bicarbonate
Disodium hydrogen phosphate
CALCIUM corbonate

Solution :NORMAL salt like calcium carbonate do not contain EITHER replaceable hydrogen ions or hydroxyl ions.
Discussion
26.

Identify the ratio of the coefficients of the products CuO,NO_(2) and H_(2)Oformed respectively when hydrated copper nitrate is thermally decomposed.2Cu(NO_(3))_(2).6H_(2)OtoNO_(2)+H_(2)O+O_(2)+2CuO

Answer»

`2:3:1`
`1:2:3`
`1 :1.5:1`
`3:2:1`

Solution :`2Cu(NO_(3))_(2).6H_(2)Oto2CuO+4NO_(2)+O_(2)+6H_(2)O`
Coefficients of CuO, `NO_(2) and H_(2)O` are RESPECTIVELY 2 , 4AND 6.
`:.` RATIO is`1:2:3`
Discussion
27.

Identify the pair of water soluble bases.

Answer»

Copper oxide, potassium oxide
Copper oxide, calcium oxide
Magnesium oxide, potassium oxide
Aluminium oxide, magnesium oxide

Solution :Magnesium oxide and potassium oxide are SOLUBLE in WATER and forming alkalies NAMELY magnesium hydroxide and potassium hydroxide RESPECTIVELY.
Discussion
28.

Identify the organic acid among the following given acids.

Answer»

Hydrochloric ACID
Nitrous acid
Carbonic acid
Stearic acid

Solution :Stearic acid is OBTAINED from LIVING SYSTEM that is from MUSTARD oil therefore it is organic acid.
Discussion
29.

Identify the odd one among the following with respect to tensile strength as well as ductility.

Answer»

GAS CARBON
Diamond
Graphite
Carbon fibre

Solution :Carbon FIBER, a recently developed allotrope of carbon is ductile and has HIGH TENSILE strength
Discussion
30.

Identify the number ofneutrons present in a pair of element with atomic numbers 20 and 13 , if their mass numbers are 40 and 27 respectively.

Answer»

20 and 13
20 and 20
17 and20
20 and14

Solution :A- Z = NUMBER of neutrons.
(1)40 - 20 = 20
(2)27 - 13 = 14
Discussion
31.

Identify the number of neutrons present in a pair of elements with atomic numbers 20 and 13, if their mass numbers are 40 and 27, respectively.

Answer»

20 and 13
20and13
17 and20
20 and14

Solution :`A-Z=n`
(1)40 - 20 =20
(2) 27 - 13 =14
Discussion
32.

Identify the layers of atmosphere as per activites mentioned and arrange them in sequence. Burning up of meteorites, flying of aeroplances, rflection of radio waves, absorption of harmful ionizing radiations and occurrence of most of the weather phenomena. (a) Troposphere (b) Stratophere ( c) Mesosphere (d) Ionophere (e ) Megnetosphere

Answer»

bcdea
cbdea
cdeab
bdaec

Solution :Burning of meteorites TAKES place in mesosphere, aeroplanes FLY in stratophere, reflection of radio waves taken place in ionosphere. MAGNETOSPHERE absorbs ionizing radiations and most of the weather PHENOMENA occurs in TROPOSPHERE.
Discussion
33.

Identify the four layers of atmosphere as per the temperature range mentioned and them in a sequence. 60^(@)C" to "-15^(@)C" to "17^(@)C" to "-51^(@)C,-15^(@)C" to "-120^(@)C and maximizing up to 2000^(@)C. (a) Troposphere (b) Stratosphere ( c) Mesosphere (d) Exosphere ( e) Thermosphere

Answer»

BACE
abce
bacd
cabe

Solution :Stratosphere has temperature range of `-60^(@)C" to "-15^(@)C`, troposphere has temperature range of `17^(@)C" to "-51^(@)C`, mesosphere has temperature range of `-15^(@)C" to "-120^(@)C` and thermospher has a maximum temperature up to `2000^(@)C`. Bace.
Discussion
34.

Identify the formula of the corresponding hydrideof a nonmetal 'X' which attainsoctet by gaining three electrons.

Answer»

XH
`XH_(2)`
`XH_(3)`
`X_(2)H_(4)`

Solution :X'should possess five valence electrons . Since its valency is 3.
Hence , its corresponding hydride is`X^(-3)H^(+1)rArrXH_(3)`
Discussion
35.

Identify the formula of the corresponding hydrideof a nonmetal 'X' which attainsoctet by gaining twoelectrons.

Answer»

XH
`XH_(3)`
`XH_(4)`
`XH_(2)`

Solution :X ATTAINS OCTET after gaining two electrons . HENCE , the valency is 2(X2) and valency of hydrogen is 1.`X^(-2)H^(+1)rArrXH_(2)`
Discussion
36.

Identify the false statement among the following.

Answer»

Compound is homogeneous in nature.
In COMPOUNDS CONSTITUENTS do not retain properties
The constituents of mixture can be separated by physical method.
during formation of mixtures there is a change in the molecular COMPOSITION

Solution :During the formation of a mixture the constituent substances are MIXED physically and hence there is no change in molecular composition during the formation of mixtures.
Discussion
37.

Identifythe components which when present in the troposphere is a pollutant and when present in upper layers of atmosphere is a protector of life.

Answer»

Chlorofluro carbons
Ozone
Nitrous oxide
Water vapour

Solution :Pzone when present in the troposphere is a major POLLUTANT that leads to global warming, while the ozone present in THETHE stratospere acts as a shield from UV rays reaching the earth's SURFACE.
Hence the ozone layer of the STRATOSPHERE acts as a shield.
Discussion
38.

Identify the common use(s) of both chile salt petre and nitre.

Answer»

Manufacture of gunpowder.
Manufacture of fertilizer.
Manufacture of glass.
All the above

Solution :Both chile SALT petre and NITRE are used in the manufacture of GUN powder, fertilizer and glass.
Discussion
39.

Identify the coefficients of the product CuO andNO2formed respectively when hydrated copper nitrate is themally decomposed.2Cu(NO_(3))_(2).6H_(2)OtoCuO+NO_(2)+6H_(2)O+O_(2)

Answer»

3 , 4
2 , 4
4 , 5
2 , 3

Solution :`2Cu(NO_(3))_(2)*6H_(2)Ooverset(Delta)to2CuO+4NO_(2)+O_(2)+6H_(2)O`
Coefficients of`CuOand NO_(2)`are respectively 2 and 4.
Discussion
40.

Identify the atomic numbers of the pair of elements whichpossessessame number of electrons in L and M shells.

Answer»

12 , 18
19 , 20
18 , 16
17 , 18

Solution :`{:("ATOMIC NUMBER (Z)","Electronic configuration"),(""19,""2_(,)8_(,)8_(,)1),(""20,""2_(,)8_(,)8_(,)2):}`
Discussion
41.

Identify the atomic number of the element which possess same number of electrons in L and M shells.

Answer»

18
19
16
18

Solution :`{:("ATOMIC NUMBER (Z)","ELECTRONIC configuration"),(""19," "2_(,)8_(,)8_(,)1),(""20," "2_(,)8_(,)8_(,)2):}`
Discussion
42.

Identify the acid used in the purification of metals like gold and silver is

Answer»

sulphuric ACID
phosphoric acid
hydrochloric acid
NITRIC acid

Solution :Nitric acid is used in the purification of metals LIKE gold and SILVER since it dissolves the impurities like VARIOUS meta oxides present on the surface of gold (or) Gold being insoluble in `HNO_(3)`, remains insoluble.
Discussion
43.

Identify physical and chemical changesamong the following.(a) Boiling of milkRipening of fruits(c ) Curding of milk(d)Melting of candle(e ) Rusting of iron(f) Blackening of silverware

Answer»

SOLUTION :`{:("Physical change ","Chemicalchange"),("Boiling of milk , melting of CANDLE","RIPENING of fruits , curdling of milk , RUSTING if iron, blackening of SILVERWARE"):}`
Discussion
44.

Identify a useful change among the following chemical changes.

Answer»

Blackening of silverware
Rusting of iron
Curding of milk
All the above

Solution :Curdling of milk results in the FORMATION of CURD which is a useful CHANGE.
Discussion
45.

Identify a false statement among the following.

Answer»

Evaporation is a surface phenomenon and CAUSES cooling.
RATE of evaporation is directly proportional to temperature.
Rate of evaporation is inversely propotional to surface AREA of liquid.
Evaporation causes cooling and depends on humidity.

Solution :Rate of evaporation is directly proportional to surface area of the liquid. Because more number of surface molecules are EXPOSED to atmosphere which gain kinetic energy and escape into atmosphere.
Discussion
46.

Identifty the xomponent which when present in the troposphere is a pollutant and when present in upper layers of atmosphereis protector of life.

Answer»

Chloroflurocarbons
Ozone
Nitrous oxide
Water vapour

Solution :Ozone when present in the TROPOSPHERE is a major POLLUTANT that LEADS to GLOBAL warming, while ozone present in the stratosphere acts as a shield from UV rays reaching the earth's surface.
Discussion
47.

(i) What is the composition of pencil leads? (ii) How are crucibles made with the help of graphite? (iii) How are crucibles made with the help of graphite? (iv) Why is graphite a more preferred lubricant to the ordinary lubricating oils? (v) What is the role of graphite in nuclear reactor?

Answer»

Solution :(i) Pencil leads are manufactured by mixing graphite with CLAY.
(II) The more theamount of clay, the harder is thepencil.
(iii) Graphite mixed with FINE clay is moulded and sintered into crucibles of desired size and shape.
(iv) Graphite is highly RESISTANT to heat andtherefore used as lubricant in those parts of machinery where HIGH heat is generated due to friction.
(v) Graphite is used in nuclear reactors as a moderator to slow down the speed of nueutrons produced due to splitting of theatoms of uranium or thorium.
Discussion
48.

(i) What are hydrocarbons? (ii) Give the formula of the simplest hydrocarbon. (iii) What is bio gas? (iv) Give two advantages of bio gas. (v) Name the products obtained on burning methane gas.

Answer»

Solution :(i) The ORGANIC compounds which contain only carbon and hydrogenare called hydrocarbon.
(II) THEFORMULA of simplest hydrocarbon is `CH_(4)`.
(iii) The DECOMPOSITION of farm waste and cow dung in the absence of air gives a mixture of gases called bio gas.
(iv) (a) It is pollution free.
(b) It has high ratio of energy given out by combustion as compared to the other fuels.
(v) Carbon dioxide andwater VAPOUR are theproducts formed on burning methane gas.
Discussion
49.

(i) Name the metal which is used in the manufacture of high voltage electric transmission wire. (ii) Why is aluminium used in the manufacture of household articles? (iii) Write the name and the formual of the monomer of polyethylene (iv) Among which alloys the percentage of zinc is less (Brass/Bronze)? (v) Why is silicone used in the manufacture of nonstick pans?

Answer»

Solution :(i) Aluminium metal is used in the manufacture of high voltage electric transmission wire.
(II) Aluminium is corrosion resistant due to surface oxide formation . Hence, used in the manufacture of HOUSEHOLD articles.
(iii) Monomer of polyethylene is ETHYLENE molecule having MOLECULAR formula ` C_(2)H_(4)`.
(iv) Bronze alloy has less percentage of zinc.
(v) Silicone is highly heat resistant, non-sticky and water REPELLENT.
Discussion
50.

(i) Name the inert gas which is used for filling weather observation balloons. (ii) Why is Radon used in cancer treatment ? (iii) Why is an alloy of tin and lead used in the manufacture of fuse wire? (iv) Name thegas which is used in advartising sign boards. (v) Why is argon used in filling electric bulbs?

Answer»

Solution :(i) Helium
(II) Radon is radioactive element.
(iii) TIN and lead have lower melting points than other merals.
(iv) Neon
(v) Argon is filled in ELECTRIC bulbs to improve the efficiency of bulb by preventing OXIDATION of tungsten FILAMENT.
Discussion