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.

The pair(s) of reagents that yield paramagnetic species is/are

Answer»

Na and excess of `NH_(3)`
K and excess of `O_(2)`
Cu and DILUTE `HNO_(3)`
`O_(2) and 2 - ethylanthraquinol

Solution :If ammonia considered as a liquid then reaction will be
A `M+(x+y)NH_(3)rarr[M(NH)_(3)_(x)]^(+)+[e(NH)_(3)_(y)]^(-)`
B `K+O_(2)rarrKO_(2)[k^(+),O_(2)^(-)`PARAMAGNETIC
C `3Cu+8HNO_(3) rarr3 Cu(NO_(3))+_(2)+2NO+4H_(2)O`
Discussion
2.

The pair(s) of ions where BOTH the ions are precipitated upon passing H_(2)S gas in presence of dilute HCl is (are)

Answer»

`BA^(2+), ZN^(2+)`
`Bi^(3+) , Fe^(3+)`
`Cu^(2+), Pb^(2+)`
`Hg^(2+), Bi^(3+)`

Solution :`Cu^(2+), Pb^(2+), Hg^(2+) and Bi^(3+)` all lie in Group II of qualitative analysis and are PRECIPITATED from the solution on passing `H_(2)S` gas in the solution ACIDIFIED with dilute HCL.
Discussion
3.

The pairs of bases in nucleic acids are held together by

Answer»

HYDROGEN bonds
Oxyribose groups
Phosphate groups
Ionic bonds

Answer :A
Discussion
4.

The pairs of bases in DNA are held together by

Answer»

HYDROGEN BONDS
Ionic bonds
PHOSPHATE groups
Deoxyribose groups

Answer :A
Discussion
5.

The pair whose both species are used in acid medicinal preparation is:

Answer»

`NaHCO _(3) andMg (OH)_(2)`
`Na_(2) CO_(3) andCa(HCO_(3))_(2)`
`Ca(HCO_(3))_(2) andMg(OH)_(2)`
`Ca(OH)_(2) andNaHCO_(3)`

ANSWER :A
Discussion
6.

The pair (s) where both the ions are precipitated upon passing H_(2)S gas in the presence of dilute HCl is (are) :

Answer»

`BA^(2+) , Zn^(2+)`
`Ba^(2+), Fe^(3+)`
`Cu^(2+) , Pb^(2+)`
`HG^(2+), Bi^(3+)`

Solution :All the ions are present in two pairs BELONGING to IInd group of basic RADICALS. They will be precipitated as their sulphides
Discussion
7.

The pair of substances that has no hydrogen bonding between them is

Answer»

`CH_3 COOH ,H_2 O`
`C_2 H_5 OH ,H_2 O`
`CH_3 CL ,H_2O`
`C_2 H_5 NH_2 ,H_2 O`

ANSWER :D
Discussion
8.

The pair of substances that has hydrogen bonding between them is

Answer»

`C_(2)H_(4),H_(2)o`
`C_(3)CHO,H_(2)O`
`CH_(3)Cl,H_(2)O`
`C_(6)H_(6),H_(2)O`

ANSWER :B
Discussion
9.

The pair of structure that are resonance hybrid is:

Answer»

`Hoverset(..)underset(..)O-OVERSET(+)(C)HCH_(3)` and `Hoverset(+)underset(..)(O)=CHCH_(3)`

`CH_(3)=overset( :O: )overset(||)(C)-H` and`{:(""overset(..)underset(..)O-H),(""|),(CH_(2)=C-H):}`
`CH_(3)overset(+)(C)H_(2)` and `overset(+)(C)H_(2) CH_(3)`

Answer :A
Discussion
10.

The pair of species with the same bond order is :

Answer»

`O_(2)^(2-), B_(2)`
`O_(2)^(+) , NO^(+)`
`NO,CO`
`N_(2) , O_(2)`

SOLUTION :Bond ORDER are`O_(2)^(2-) = 1.0, B_(2) = 1.0, O_(2)^(+) = 2.5 `
` NO^(+) = 3 NO = 2.5 , CO = 3, N_(2) = 3, O_(2) = 2 `
THUS , `O_(2)^(2-) and B_(2)` have tha same bond order viz 1.
Discussion
11.

The pair of species with the same bond order is

Answer»

`NO, CO`
`NO^(+), O_(2)^(+)`
`N_(2),O_(2)`
`O_(2)^(2-), B_(2)`

ANSWER :d
Discussion
12.

The pair of molecules forming strongest inter molecular hydrogen bonds are

Answer»

`SiH_4 and SiF_4`
`H_2 OAND NH_3`
`CH_3 COCH_3 and CHCl_3`
`H- overset(O ) overset(||)C-OH andCH_3 - overset(O ) overset(||)C -OH`

ANSWER :D
Discussion
13.

The pair of ions having same electronic configuration is.....

Answer»

`Cr^(3+) , Fe^(3+)`
`Fe^(3+), Mn^(2+)`
`Fe^(3+), Co^(3+)`
`SC^(3+), Cr^(3+)`

SOLUTION :`Cr^(3+) = [Ar]^(18) 3d^(3), Fe^(3+) = [Ar]^(18) 3d^(5), Mn^(2+) = [Ar]^(18) 3d^(5)`
THUS, `Fe^(3+) and Mn^(2+)` have the same ELECTRONIC CONFIGURATION
Discussion
14.

The pair of elements with the following atomic numbers are chemically similar

Answer»

13, 12
13, 15
3, 11
2,8 8. 

Answer :C
Discussion
15.

The pair of elements with same electronegatively and stardard oxidation potential are

Answer»

Mg and CA
Ca and Sr
Ca and Ba
Ba and Be

Solution :Sr has small size than expected due to POOR SHIELDING of d - orbitals, so both `Ca^(+2) and Sr^(+2)` have same HYDRATION energy there by sameoxidation potential.
Discussion
16.

The pair of elements do not impart flame colour test

Answer»

`Be & CA`
`Ca & MG`
`Mg & BA`
`Be & Mg`

ANSWER :D
Discussion
17.

The pair of compunds in which both the metals are in the highest possible oxidation state is:

Answer»

`[FE(CN)_(6)]^(3-) and [CO(CN)_(6)]^(3-)`
`CrO_(2)CI_(2) and MnO_(4)`
`TiO_(3) and MnO_(2)`
`[CO(CN)_(6)]^(3-) and MnO_(2)`

SOLUTION :`Cr_(2)O_(2)CI_(2) (+6) andMnO_(4)^(-)(+7)`
Discussion
18.

The pair of compounds which cannot exist together is

Answer»

`NaHCO_(3)` and NaOH
`Na_(2)CO_(3)` and `NaHCO_(3)`
`Na_(2)CO_(3)` and NaOH
`NaHCO_(3)` and NaCl.

SOLUTION :An acid salt `(NaHCO_(3))` cannot EXIST with a base (NaOH) in a solution.
Discussion
19.

The pair of compounds which cannot exist together in solution is

Answer»

`NaHCO_(3)` and NaOH
`NaHCO_(3)` and `H_(2)O`
`NaHCO_(3)` and `Na_(2)CO_(3)`
`Na_(2)CO_(3)` and NaOH.

Solution :A base (NaOH) and ACID SALT `(NaHCO_(3))` cannot exist TOGETHER in solution.
Discussion
20.

The pair of compounds which cannot exist together in aqueous solution is

Answer»

`Na_(2)CO_(3)` and `NaHCO_(3)`
`NaHCO_(3)` and NaOH
NaOH and `NaH_(2)PO_(4)`
Both (B) and (C ).

SOLUTION :The pairs would involve acid base reaction to form salt and water.
`NaHCO_(3)+NaOH rarrNa_(2)CO_(3)+H_(2)O`
`2NAOH + NaH_(2)PO_(4)rarrNa_(3)PO_(4)+2H_(2)O`
Discussion
21.

The pair of compounds which cannot exist together in aqueous solution are

Answer»

`NaH_(2)PO_(4)` and `Na_(2)HPO_(4)`
`Na_(2)O_(3)` and `NaHCO_(3)`
NaOH and `NaH_(2)PO_(4)`
`NaHCO_(3)` and NaOH.

SOLUTION :A base (NaOH) and an acid SALT `(NaH_(2)SO_(4) " or "NaH_(2)PO_(4))` cannot EXIST TOGETHER in a solution.
Discussion
22.

The pair of compounds that will not react with each other in an aqueous solution, at room temperature is

Answer»

`FeCl_(3),SnCl_(2)`
`HgCl_(2),SnCl_(2)`
`FeCl_(2),SnCl_(2)`
`FeCl_(3),Kl`

ANSWER :C
Discussion
23.

The pair of compounds that can exist together is :

Answer»

`FeCl_(3),SnCl_(2)`
`HgCl_(2),SnCl_(2)`
`FeCl_(2),SnCl_(2)`
`FeCl_(3),KI`

Solution :`FeCl_(2)andSnCl_(2)` (both are reducing AGENT and have lower OXIDATION no.)
Discussion
24.

The pair of compounds that can exist together is

Answer»

`FeCI_(3),SnCI_(2)`
`H_(g)CI_(2),SnCI_(2)`
`FeCI_(2),SnCI_(2)`
`FeCI_(3),KI`

SOLUTION :`FeCI_(2) and SnSOI_(2)` can exist TOGETHER SINCE `SN^(2+)` ions connot reduce `Fe^(2+)` ions
Discussion
25.

The pair of compounds having metals in their highest oxidation state is:

Answer»

`MnO_(2) and CrO_(2)Cl_(2)`
`[FeCl_(4)]^(-) and Co_(2)O_(3)`
`[Fe(CN)_(6)]^(3-) and [Cu(CN)_(4)]^(2-)`
`[NiCl_(4)]^(2-) and [CoCl_(4)]^(2-)`

Answer :C
Discussion
26.

The pair of compounds having metals in their highest oxidation state is

Answer»

`MnO_(2)FeCI`
`MnO_(4)^(-)CrO_(2)CI_(2)`
`[Fe(CN)_(6)]^(3-),COCI_(4)]^(-)`
`[NiCI_(4)]^(2-),[CoCI_(4)]^(-)`

Solution :HIGHEST O.S of Mn is +7 `MnO_(4)^(-)` and that of Cr is +6 `CrO_(2)CI_(2)`
Discussion
27.

The pair of compounds having metals in their highest oxidation state is "________________".

Answer»

`MnO_(2) , FeCl_(3)`
`V_(2) O_(5) , CrO_(3)`
`Mn_(2)O_(3) , V_(2) O_(3)`
` V_(2)O_(3) , SnCl_(2)`

Answer :B
Discussion
28.

The pair of compound which cannot exit together in solution is

Answer»

`NaHCO_(3) and H_(2)O`
`Na_(2)CO_(3) and NAOH`
`NaHCO_(3) and NaOH`
`NaHCO_(3) and Na_(2)CO_(3)`

ANSWER :C
Discussion
29.

The pair of boiling point and compound ar given as, {:(C_6H_6, CH_3OH, C_6H_5NO_2, C_6H_5NH_2),(80^@C, 65^@C, 212^@C, 184^@C),(I,II,III,IV):} Which will show lowest vapour pressure at room temperature

Answer»

`C_6H_6`
`CH_3OH`
`C_6H_5NO_2`
`C_6H_5NH_2`

ANSWER :B
Discussion
30.

The pair of atomic numbers which represent the p-block elements

Answer»

6,12
7,53
19,35
38,51

Answer :B
Discussion
31.

The pair o f ions configuration is ....

Answer»

`Cr^(3+), Fe^(3+)`
`Fe^(3+), Mn^(2)`
`Fe^(3+), Co^(3+)`
`Sc^(3+), Cr^(3+)`

SOLUTION :
So, `Fe^(3+) and Mn^(2+)`have the same ELECTRONIC configureation.
Discussion
32.

The pair of amphoteric hydroxides is

Answer»

`Be(OH)_(2)`,`Al(OH)_(3)`
`Al(OH)_(3)`, `LiOH`
`B(OH)_(3)`, `Be(OH)_(3),Be(OH)_(2)`
`Be(OH)_(2)`, `Mg(OH)_(2)`

SOLUTION :`Be(OH)_(2)` and `Al(OH)_(3)` are AMPHOTERIC
Discussion
33.

The pair in which phosphorous atoms have a formal oxidation state of +3 is

Answer»

orthophosphorous acid and pyrophosphorous acids
pyrophosphorous acid and hypophosphoric acids
orthophosphorous and hyphophosphoric acids
pyrophosphorus and pyrophosphoric acids

Solution :The O. S of P is given in the BRACKET. Orthophoshorus acid, `H_(3)PO_(3)(+3)`,
Pyrophosphorus acid, `H_(4)P_(2)O_(5)(+3)`,
Hypophosphoric aicd, `H_(4)P_(2)O_(6)+(4)` and
Pyrophosphoric acid, `H_(4)P_(2)O_(7)(+5)`.
Discussion
34.

The pair in which phosphorusatoms have a formal oxidation state of +3is

Answer»

orthophosphorus and pyrophosphorus acid
pyrophosphorus and hypophosphoric acid
orthophosphorus and hypophosphoric acid
pyrophosphorus and pyrophosphoric acid

Solution :Orthophosophrousacid : `overset(+1+3-2)(H_(3)PO_(3))`

LET the oxidation NUMBER of P in pyrophosphorus acid be x.
So, 4(+1)+2x+5(-2)=0
or ,2x=6 or, x=+3
Discussion
35.

The pair having similar geometry is

Answer»

`BF_(3) , NH_(3)`
`H_(2)O,C_(2)H_(2)`
`CO_(2)SO_(2)`
`NH_(3),PH_(3)`

Answer :D
Discussion
36.

The packing fraction of a simple cubic unit cells ________

Answer»


ANSWER :0.524 or 52.4%
Discussion
37.

The packing efficiency of the two dimensional square unit cell show in the adjoining fig ,. Is (##PR_CHE_V01_XII_C01_E20_009_Q01.png" width="80%">

Answer»

0.3927
0.6802
0.7405
0.7854

Solution :In the two - dimensional packing , packing FRACTION
Area occupied by circles
` (" within the square")/("Area of the square") `
` ( 2 xx pir^(2))/a^(2) `
AC = `SQRT(AB^(2) + BC^(2)) = sqrt(a^(2) + a^(2)) = sqr2 a `
but AC = 4 r( r= radius of each sphere)
` sqrt2 a= 4R or a = 4/sqrt2 r = 2 sqrt2r`
packing fraction
` ( 2XX pi r^(2))/((2 sqrt2 r)^(2))= pi/4 = ( 3.143)/4 = 0.785i.e, 78.5%`
Discussion
38.

The packing effciencyof the two dimensional cell square unit as shownis

Answer»

0.3927
0.6802
0.7405
0.7854

Solution :Package EFFICIENCY = `("AREA COVERED by particle")/("Total area")`If a is the LENGTH of unit cell,
Area of unit all=`a^(2)`

`"Face diagonal " AC=sqrt2a`
`"But" "" AC = 4r`
`therefore""sqrt2a =4r`
`or""a = 2sqrt2r`
`"No. of""""PARTICLES" = 4times1/4+1=2`
`"Area occupied by particles" = 2timespir^(2)`
`"Packing efficiency" = (2timespir^(2))/((2sqrt2r)^(2))=pi/4=0.7857`
=`78.57%`.
Discussion
39.

The p pi- p piback bonding occurs in the halides of boron and not in those of aluminium. Explain.

Answer»

<P>

Solution :The tendency to show `p pi -p pi` BACK bonding depends upon the size of central ATOM. This tendency decreases as the size of the central atom in a group increases.
SINCE aluminium has LARGER size than boron, the back bonding is not possible.
Discussion
40.

The P-P-P angle in P_(4) molecule is …………..degree while S-S-S angle in S_(8) is ………..degree.

Answer»


ANSWER :`60^(@),107^(@)`
Discussion
41.

the ozonolysis product(s) of the following reaction is(are) CH_(3)CH_(2)-C-=CH underset("(ii) "H_(2)O)overset((i)" "O_(3))toproduct(s)

Answer»

`CH_(3)COCH_(3)`
`CH_(3)COCH_(3)+HCHO`
`CH_(3)COOH+HCOOH`
`CH_(3)CH_(2)COOH+HCOOH`

Answer :D
Discussion
42.

The ozonolysis product of an alkyne is 2-oxopentanal. Then the alkyne is___________

Answer»

Solution :2-oxopentanal is `CH_(3)-CH_(2)-CH_(2)-underset(O)underset(||)C-underset(O)underset(||)CH`
HENCE the triple BOND should be present between `C_(1)` and `C_(2)`, so that the alkyne is 1-pentyne.
`CH_(3)-CH_(2)-CH_(2)-C-=CH`
Discussion
43.

The ozone layer protecting the lives is situated in the troposphere.

Answer»

SOLUTION :FALSE (OZONE layer is SITUATED in the stratosphere.)
Discussion
44.

The ozone layer is depleted by

Answer»

NO
`SO_2`
`C_x H_y`
CFCS

Solution :OZONE LAYER is DEPLETED by NO as WELL as CFCs.
Discussion
45.

The oxygen needed for complete combustion of 4 gm CH_(4) may be obtained from decomposition of :

Answer»

`(4)/(3)` moles of `KCIO_(3)` with 25% YIELD `(KCIO_(3) rarr KCI+(3)/(2)O_(2))`
50 ml, 10 m`H_(2)O_(2)`SOLUTION `(H_(2)O_(2)rarr H_(2)O+(1)/(2)O_(2))`
500 gm solution containing 17% (w/w)`NaNo_(3)` `(NaNo_(3)rarr NaNO_(2)+(1)/(2))`
410 gm impure sample of `Ca(NO_(3))_(2)` of 40% purity`(Ca(NO_(3))_(2) rarr CaO + 2NO_(2) +(1)/(2)O_(2))`

Answer :A::C::D
Discussion
46.

The oxoacid of phosphorus that reduces silver nitrate into metallic silver is

Answer»

`H_(3)PO_(2)`
`H_(4)P_(2)O_(6)`
`H_(3)PO_(4)`
`H_(4)P_(2)O_(7)`

Solution :Refer to page 11/136. Due to the presence ONE P-H bond in `H_(3)PO_(2)`, it acts as a reducing AGENT and hence reduces `AgNO_(3)` to metallic AG.
Discussion
47.

The oxisation of SO_(2) and O_(2) to SO_(3) is an exothermic reaction. The yield of SO_(3) will be maximum if

Answer»

Temperature and PRESSURE both are increased
Temperature DECREASED, pressure increased
Temperature increased, pressure constant
Temperature and pressure both decreased

ANSWER :B
Discussion
48.

The oxidising agent in the reaction 2MnO_(4)^(-) +16H^(+) +5C_(2)O_(4)^(-2) rarr 2Mn^(+2) +8H_(2)O +10CO_(2)

Answer»

`MnO_(4)^(-)`
`H^(+)`
`C_(2)O_(4)^(2-)`
Both 1 & 2

Solution :Oxidising agent UNDERGO reduction
Discussion
49.

The oxides which give H_(2)O_(2) on treatment with dilute acid are

Answer»

`PbO_2`
`MnO_2`
`Na_2O_2`
`BaO_2`

Solution :`Na_2O_2 , BaO_2` are PEROXIDES which on REACTION dil. ACIDS GIVE `H_2O_2`
Discussion
50.

The oxides of nitrogen contain 63.65%, 46.69 and 30.64% of nitrogen respectively. This data illustrate the law of

Answer»

CONSTANT Proportions
Multiple Proportions
Reciprocal Proportions
Conservation of MASS

ANSWER :B
Discussion