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.

Which substance possess B_3N_3H_6 molecular formula ?

Answer»

Boric ACID
Boron nitrogen HYDRIDE
BORAZINE
Boron nitride

Answer :C
Discussion
2.

Write the relation between Delta H and Delta U.

Answer»

Solution :`Delta H = Delta U + Delta n. RT` where R is GAS constant= 8.314 J/K mole T is the temperature in kelvin
`Delta n` = Number of MOLES of GASEOUS products - Number of moles of gaseous reactants.
Discussion
3.

What is the oxidation number of the metals [Fe(CN)_6]^(4-)

Answer»

Solution :Fe in `[Fe(CN)_6]^(4-)` . LET the oxidation number of Fe in `[Fe(CN)_6]^(4-)` be x and CN be -1
i.e., `oversetx(Fe)OVERSET(-)((CN))_6`
`therefore` SUM of oxidation number of all the atoms in `[Fe(CN)_6]^(4-)=x+6(-1)=-4,x-6=-4,x=+2`
Thus, the oxidation number of Fe in `[Fe(CN)_6]^(4-)` is +2.
Discussion
4.

What are electrophiles? Give an example.

Answer»

SOLUTION :Electrophiles: are reagents that are ATTRACTED towards NEGATIVE charge on rich center. They are either positively charged ions or electron deficient neutral MOLECULES.
Example, `CO_2 AICI_3, BF_3 FeCI_3, NO^(+), NO_(2)^(+)`.etc.
Discussion
5.

When one mole of an ideal gas is compressed to half of its initial volume and simultaneously heated to twice its initial temperature, the change in entropy of gas (Delta S) is

Answer»

`C_(p, m) ln 2`
`C_(V, m) ln 2`
R ln 2
`(C_(v, m)- R) ln 2`

SOLUTION :`DELTA S = nC_(v) "ln " (T_(2))/(T_(1)) + nR "ln . (V_(2))/(V_(1))`
`=1 XX C_(v) ln 2 + 1 xx R "ln " (1)/(2) = ln = (C_(v)- R)`
Discussion
6.

When sodium metal is dropped in liquid NH_3 it forms Na^(+) and gets ammoniated. Which of the following forces are responsible for the formation of ammoniated sodium ion.

Answer»

ION-induced dipole 
Dipole - dipole 
Ion - dipole 
Dipole-induced dipole 

Solution :`NA^(+)` surrounded by POLAR `NH_3`.
Discussion
7.

When NaNO_(3) is heated in a closed vessel, O_(2) is liberated and NaNO_(2) is left behind. At equilibrium: NaNO_(3(g)) hArr NaNO_(2(g)) + (1)/(2) O_(2(g))

Answer»

addition of `NaNO_2` favours reverse reaction
addition of `NaNO_2` favours FORWARD reaction
increasing temperature favours forward reaction
increasing pressure reduces the RATE of forw ARD reaction

Solution :Le-chatelier.s principle
Discussion
8.

Which of the following reagent(s) make distinction of acetate from oxalates and formates?

Answer»

`BaCI_(2)`
`CaCI_(2)`
`HgCI_(2)`
`FeCI_(3)`

ANSWER :A::B::C
Discussion
9.

Verify the law of reciprocal proportions from the following data : KCl contains 52.0 % potassium , KI contains 23.6 % potassium while Icl contains 78.2 % iodine.

Answer»

Solution :Let 1 g of potassium (K) be the FIXED WEIGHT
In KCl, 52.0 g of K are COMBINED with Cl = 48.0 g
1.0 g of K are combined with `Cl = (48.0)/(52.0)g = 0.092 g`
In KI, 23.6 g of K are combined with `I = 76.4 g`
1.0 g of K is combined with `I = (76.4)/(23.6)g = 3.24 g`
Ratio by weight of I and Cl combined with 1.0 g of K in the two halides `= (3.24)/(0.92)`
In ICI, ratio by weight of I and Cl `= (78.2)/(21.8)`
COMPARING the two ratios :
`(3.24)/(0.92):(78.2)/(21.8)or 3.52:3.59`
Since the two ratios are nearly the same, this verifies the Law of Reciprocal Proportions.
Discussion
10.

Write the condensed formulae for each of the following compounds : (i) Isopropyl alcohol(ii) Methyl t-butyl ether (iii) 2-Chloro-1, 1, 1-trifluoroethane(iv) 2-Methylbuta-1, 3-diene(v) But-2-en-1-ol

Answer»

Solution :(i) `(CH_(3))_(2)CHOH`(ii) `CH_(3)-O-C(CH_(3))_(3)`(III) `F_(3)C-CH_(2)Cl`
(iv) `{:(""CH_(3)),("|"),(CH_(2)=C-CH=CH_(2)):}` (V) `CH_(3)CH=CHCH_(2)OH`
Discussion
11.

What is meant by elastic collision?

Answer»

Solution :Elastic collision means that the total ENERGY of molecules before and after collision remains same. There may be exchange of energy between COLLIDING molecules.
Their individual ENERGIES may change, but the average energy remains CONSTANT.
Discussion
12.

Which of the following compounds will decarboxylate to form ketone ?

Answer»

`CH_(3)CH_(2)COCH_(2)COOH`
`CH_(3)COCH_(2)CH_(2)COOH`
`CH_(3)COOH`
None of these

Solution :`beta-`Keto acids decarboxylate easily due to the FORMATION of a six membered cyclic transition state by intramolecular HYDROGEN bonding
Discussion
13.

Which of the following CORRECTLY represents the reactions occuring in Daniel cell ?

Answer»

`CH_(4(g)) + O_(2(g)) RARR CO_(2(g)) + 2H_(2)O_((l))`
`Mg_((s)) + O_(2(g)) rarr MgO_((s))`
`Zn_((s)) + Cu_((aq))^(2+)rarr Zn_((aq))^(2+) + Cu_((s))`
`2ZnS_((s)) + 3O_(2(g)) overset("heat")(rarr) 2ZnO_((s))+ 2SO_(2(g))`

Answer :C
Discussion
14.

Which one of the following gives onlyh one monochloro derivative?

Answer»

neo-Pentane
n-Hexane
2-ethylpentane
3-Methylpentane

Solution :neo-Pentane or 2,2-dimethylpropane has only PRIMARY HYDROGEN hence it can give only monochloro derivative. All other COMPOUNDS have `1^(@),2^(@) and 3^(@)` hydrogens hence they give MONO, di or trisubstituted products.
Discussion
15.

Which of the following statement about IV group elements ( C to Pb) is not correct

Answer»

The thermal stability of hydrides decreases from `CH_(4)" to "PbH_(4)` as bond enthalpy for M - H bond decreases
All form tetra fluorides, tetra CHLORIDES, tetra bromides
Only Sn and PB form dichlorides
All form tetra iodides

Solution :For example `PbI_(4)` does not exist because `Pb^(4+)` ion is string oxidising agent and `I^(-)` ion and GETS reduced to `Pb^(2+)` ion
Discussion
16.

The volume of liberated at STP from 20ml of Vol H_(2)O_(2) is

Answer»

20 ml
10ml
200ml
100 ml

Solution :VOL of OXYGEN ` = 20 xx 10 mL`
Discussion
17.

Which of thefollowingsentences is not true ?

Answer»

Lightisa BEAM of PHOTON
Lighthaswavenatureso itdiffracted.
Lighthasparticlenatureso balckbodyradiationobserve.
Lightrequireair asmedium

ANSWER :D
Discussion
18.

What is the molecular formula of carvone ?

Answer»

`C_(8)H_(10)O`
`C_(10)H_(14)O`
`C_(10)H_(12)O`
`C_(9)H_(12)O`

ANSWER :B
Discussion
19.

Which of the following compounds can prefer E^(1)cb mechanism over E^(2) ?.

Answer»




SOLUTION :B, C - can FORM stable CARBANIONS
Discussion
20.

Which one of the following can exist in optically active forms?

Answer»

cis-1,3-Dichlorocyclohexane
trans-1,3-Dichlorocyclohexane
cis-1,4-Dichlorocyclohexane
trans-1,4-Dichlorocyclohexane

Solution :trans-1, 3-Dichlorocyclohexane
Discussion
21.

Which allotropes of phosphorous is most stable ?

Answer»

BLACK P
Red P
Yellow P
White P

Answer :A
Discussion
22.

Which one is a wrong statement ?

Answer»

The VALUE of m for `d_z^2`is ZERO.
Total orbital angular momentum of electron in 's' orbital is equal to zero.
The electronic CONFIGURATION of N atom is

An orbital is designated by three quantum numbers while and electron in an atom is designated by four quantum numbers.

SOLUTION :All the 2p orbital has parallel spin of electron in correct electronic configuration of N atom.
Discussion
23.

Which of the following do not represent ground state electronic configuration of an atom ?

Answer»

`1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(8)4s^(2)`
`1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(9)4s^(2)`
`1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(10)4s^(1)`
`1s^(2)2s^(2)2p^(6)3s^(2)3p^(6)3d^(5)4s^(1)`

Answer :B
Discussion
24.

What is the mass percentage of carbon in ethane.

Answer»


ANSWER :0.8
Discussion
25.

Write the relation between Delta G^(@) and equilibrium constant.

Answer»

`Delta G^(@) = -2.303 RT LOG K`
` Delta G^(@) = - RT log K`
` Delta G^(@) = 2.303 RT log K`
` Delta G^(@) = -2.303 log K`

Solution :Consider a reversible reaction, `A + B hArr C + D`. The RELATIONSHIP between Gibb's free ENERGY change `(Delta G)` at any TIME and standard Gibb's free energy change `(Delta G^(@))` of the reaction is `Delta G = Delta G^(@) + RT ln Q` where `Q = (p_(C ).p_(D))/(p_(A).p_(B))` at any given time.
This equation is called "Van't Hoff's reaction isotherm.". When the reaction attains equilibrium, `Delta G = 0` and `(p_(C ).p_(D))/(p_(A).p_(B)) = K`. The above equation becomes,
`0 = Delta G^(@) + RT ln K`
or `Delta G^(@) = -RT ln K`
`:. Delta G^(@) = -2.303 RT log K`
`Delta G^(@)` is the standard free energy change of the reaction, R is the gas constant, T is the temperature in absolute scale and `K_(p)` is the equilibrium constant
In general, for `aA + bB hArr c C + d D`
`Delta G^(@) = -2.303 RT log K_(p)` where `K_(p) = (p_(C ).p_(D))/(p_(A).p_(B))`
Discussion
26.

Which of the following is the correct IUPAC name ?

Answer»

3-ethyl-4, 4-dimethylheptane
4, 4-dimethyl-3-ethylheptane
5-ethyl-4, 4-dimethylheptane
4, 4-bis(methyl)-3-ethylheptane

Solution :`OVERSET(7)(C )H_(3)- overset(6)(C )H_(2)- overset(5)(C )H_(2) - underset(underset(CH_(3))(|))overset(overset(CH_(3))(4|))(C )- overset(overset(C_(2)H_(5))(3|))(C )H- overset(2)(C )H_(2) - overset(1)(C )H_(3)`
According to alphabetical order methyl is written after ethyl. To write prefixes di of two `-CH_(3)`
Discussion
27.

What do you understand by isoelectronic species ? Name a species that will be isoelectronic with each of the following atoms or ions. (i) F^(-)"" (ii) Ar"" (iii) Mg^(2+) "" (v) Rb^(+)

Answer»

Solution :Number of electrons in ATOM or IONS are same than it is called .isoelectric species..
e.g. `O^(2-) , F^(-) , Na^(+) , Mg^2+)`ions having 10 electrons and isoelectric species.
Radius of isoelectric species are different because nuclear charge are different.
In isoelectric species, nuclear charge increases radius decreases so radius increases like `Mg^(2+) lt Na^(+) lt F^(-) lt O^(2-) `because nuclear charge decreases like 12, 11, 9, 8.
Discussion
28.

The region which contains water vapour is

Answer»

STRATOSPHERE
TROPOSPHERE
Mesophere
THERMOSPHERE

ANSWER :B
Discussion
29.

What is the role of builder in synthetic detergents?

Answer»

Solution :It REMOVES hardness PRODUCING ions VIZ., `Ca^(2+)` and `MG^(2+)` ions
Discussion
30.

Which one of the following is not a transuranic element ?

Answer»

Californium
Thorium
Curium
Lawrencium

Answer :B
Discussion
31.

Which of the following pairs of d-orbitals will have electron along the axes?

Answer»

`d_(z^2), d_(XZ)`
`d_(xz),d_(yz)`
`d_(z^2), d_(x^2-y^2)`
`d_(XY), d_(x^2)-y^(2)`

ANSWER :C
Discussion
32.

What is dead burnt plaster ? Why is it so called ?

Answer»

Solution :When gypsum or PLASTER of Paris is heated above 393 K , it loses all the water of CRYSTALLIZATION and anhydrous calcium sulphate is obtained .
`Caunderset("Gypsum")(SO_(4).2H_(2)) O overset( gt 393K)(to) underset("Dead burnt plaster")(CaSO_(4)) + 2H_(2)O`
`2 underset("Plaster of Paris")(CaSO_(4).2H_(2)) O overset(gt 393 K)(to) 2 CaSO_(4) + H_(2)O`
Anhydrous calcium sulphate does not absorb water to form gypsum and HENCE loses the properties of setting with water . That is why anhydrous calcium sulphate is called dead burnt plaster .
Discussion
33.

Which of the following lattices has the highest packing efficiency ? (i) Simple cubic (ii)body-centred cubic (iii) hexagonal close-packed lattice..

Answer»

SOLUTION :packing efficiencies are : simple CUBIC = 52.4% , BODY - centred cubic = 68% , HEXAGONAL close-packed = 74 % thus, hexagonal close - packed lattice has the highest packing EFFICIENCY.
Discussion
34.

Which conformation of ethane has the lowest potential energy?

Answer»

Eclipsed
skew
Staggered
all will have equal POTENTIAL ENERGY

Solution :Staggered CONFORMATION of ETHANE has the LOWEST potential energy.
Discussion
35.

Which of the following is called Lucas reagent?

Answer»

CONC. `H_2SO_4` + ANHYDROUS `CuSO_4`
Conc.HCI + Anhydrous `ZnCl_2`
Dil.HCI + `AlCl_3`
Conc.HCI +Conc. `HNO_3`

SOLUTION :Conc.HCI + Anhydrous `ZnCl_2`
Discussion
36.

Water softened by permutitt process contains

Answer»

<P>Dissolved SODIUM salts
Dissolved gases
Does not give good lather with soap
Dissolved CALCIUM salts

Solution :`(Na_(4)P_(2)O_(6))^(-2)+Ca^(+2) RARR (CaNa_(2)P_(2)O_(6))^(-2)+2NA^(+)`
Discussion
37.

Which of the following sets of ions represents the collections of isoelectronic species?

Answer»

`K^(+), CA^(2+), Sc^(3+), Cl^(-)`
`Na^(+), MG^(2+), Al^(3+), Cl^(-)`
`K^(+), Cl^(-), Mg^(2+), Sc^(3+)`
`Na^(+), Ca^(2+), Sc^(3+), F^(-)`

Solution :
Discussion
38.

Which of the following is a wrong statement ?

Answer»

The reacting species in SULPHONATION is `H_2SO_4`
In Friedel-Crafts reaction of benzene with an ACID CHLORIDE the electrophilic reagent is `RCO^(+)`
In the nitration of toluene by electrophilic substitution the ELECTROPHILE is nitronium ion 
Reaction of benzene with chlorine in the presence of sunlight is an addition reaction

Answer :A
Discussion
39.

Which one is not correct for the reaction (CN)_(2) + H_(2)O rarr HCN + HOCN?

Answer»

It is an auto REDOX change
Ox.no. of C in `(CN)_2`HCN and HOCN are +3, +2 and +4 respectively
Ox.no. of N in `(CN)_2`HCN and HOCN are +3, +2 and +4 respectively
The resultant solution is acidic

Solution :`overset(-3)((CN))_2+H_(2)Orarroverset(-3)(HCN)+overset(-3)(HOCN)`
Discussion
40.

Phosphorus on reaction with NaOH produces PH_(3) and NaH_(2)PO_(2). This reaction is an example of

Answer»

oxidation
reduction
DISPROPORTIONATION
neutralisation

Answer :C
Discussion
41.

What is organic chemistry?

Answer»

Solution :The carbon FORMS covalent bonds with other carbon and also with other elements like hydrogen oxygen, nitrogen, SULPHUR, PHOSPHORUS and halogen. The resulting compound are studies under a separate branch of chemistry called ORGANIC chemistry
Discussion
42.

Which of the following is not an example of friedel-craft reaction.

Answer»




None of the above

SOLUTION :A and B are EXAMPLES of FRIEDEL - craft alkylation which C is an example of intramolecular friedel craft reaction.
Discussion
43.

When an electric discharge is passed through hydrogen gas, the hydrogen molecules dissociate to produce excited hydrogen atoms. These excited atoms emit electromagnetic radiation of discrete frequencies which can be given by the general formula bar(v) = 109677 [(1)/(n_(i)^(2))- (1)/(n_(2)^(f))] What points of Bohr's model of an atom can be usedto arrive at this formula ? Based on these points derive the above formula giving description of each step and each term.

Answer»

Solution :Two important points of Bohr's model that can be used to derive the given formula are:
(i) Electrons revolve AROUND the nucleus in stationary states, i.e., orbits with fixed values of energy (quantized values).
(ii) Energy is EMITTED or absorbed only when electron jumps from one orbit to another
Derivation. Step (i) The energy of the electron in the nth stationary state is given by
`E_(n) = - (2pi^(2) me^(4))/(n^(2)h^(2))`
where m = mass of electron, e= charge on electron, h = Planck's constant
Step (ii). When th electron jumps from outer stationay state `n_(2)` to inner stationary state `n_(1)`, the different of energy `(Delta E)` is emitted, i.e.,
`Delta E = E_(2) - E_(1) = - (2pi^(2) me^(4))/(n_(2)^(2) h^(2)) - (-(2pi^(2) me^(4))/(n_(1)^(2) h^(2))) = (2pi^(2) me^(4))/(h^(2)) ((1)/(n_(1)^(2)) - (1)/(n_(2)^(2)))`
Step (iii), `Delta E = hv = h(c)/(LAMDA) = hc BAR(v)`
`:. bar(v) = (Delta E)/(hc) = (2pi^(2) me^(4))/(ch^(3)) ((1)/(n_(1)^(2)) - (1)/(n_(2)^(2)))`
Substituting the value of the constant, `pi, m, e, c and h` in CGS units, we get
`bar(v) = 109677 cm^(-1) ((1)/(n_(1)^(2)) - (1)/(n_(2)^(2)))`
Discussion
44.

Which of the following can act both as oxidising agents and reducing agents?

Answer»

`HNO_(2)`
`H_(2)O_(2)`
`H_(2)S`
`SO_(2)`

SOLUTION : These can undergo INCREASE as WELL as decrease in oxidation number
Discussion
45.

Write the structural formula of the following compounds : (i) 2- Chloro- 2- Methylpropane (ii) 1- Bromo-2 , 2-Dimethylpropane

Answer»

SOLUTION :(i) 2 - Chloro-2- Methylpropane <BR> `CH_(3)- overset(CH_(3))overset(|)underset(Cl) underset(|)(C)- CH_(3)`
(ii) 1- Bromo-2 , 2- DIMETHYLPROPANE
`CH_(3) - overset(CH_(3))overset(|)underset(CH_(3))underset(|)(C) - CH_(2) Br`
Discussion
46.

When n=3, 1 =1, the designation given to the orbital is

Answer»

`4S`
`4P`
`3S`
`3P`

ANSWER :D
Discussion
47.

Write the position isomers of (a) C_(3)H_(6)Cl_(2) (b) C_(3) H_(5) Cl

Answer»

Solution :The number of POSITION isomers for the formula `C_(3)H_(6)CI_(2)`. Is four.
`(1)underset(1,1-"Dichloropropane")(CH_(3)-CH_(2)-CHCI_(2))`
`(2) underset(2,2-"Dichlorophane")(CH_(3)-C CI_(2)-CH_(3))`
(3) `underset(1,2-"Dichloroprophane")(CH_(3)-CHCI-CH_(2)CI)`
(4) `underset(1,3-"Dichloropropane")(CH_(2)CI-CH_(2)CI)`
(B) The number of position isomers for the formula `C_(3)H_(5)CI` is three.
(1) `underset(3-"Chlorpropane")(CH_(2)=CH-CH_(2)CI)`
(2) `underset(2-"Chloropropane")(CH_(2)=C CI-CH_(3))`
(3) `underset(1-"Chloropropane")(CHCI=CH-CH_(3))`
Discussion
48.

Which of the following statement is not correct about the characteristics of cathode rays

Answer»

They START from the cathode and move towards the anode.
They travel in straight line in the absence of an external electrical or magnetic field.
Characteristics of cathode rays do not depend UPON the MATERIAL of electrodes in cathode ray tub
Characteristics of cathode rays depend upon the nature of gas present in the cathode ray tube.

Solution :Cathode rays has negatively charged material PARTICLES called electrons. It was discovered by William Crookes. The characteristics of cathode rays do not depend upon the m aterial of electrodes and the nature of the gas present in the cathode ray tube
Discussion
49.

When zeolite, which is hydrated sodium aluminium silicate, is treated with hard water, the sodium ions are exchanged with

Answer»

`H^(+)` IONS
`Ca^(2+)`
`SO_(4)^(2-)` ions
`MG^(2+)` ions

Answer :B::D
Discussion
50.

When SO_2is passed in acidified potassium dichromate solution, the oxidation state of S is changedfrom:

Answer»

`+ 4` to 0
`+ 4` to +2
` + 4` to + 6
` + 6` to + 4

Solution :`OVERSET(+5)(SO_4)RARROVERSET(+6)(H_2SO_4)`
Discussion