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.

How many stereoisomers does the molecules have ? CH_(3)CH=CHCH_(2)CHBrCH_(3)

Answer»

`2`
`4`
`6`
`8`

ANSWER :B::D
Discussion
2.

How many stereoisomers are possible for product P ?

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SOLUTION :
Discussion
3.

How many stereoismers are possible for the following compound?

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SOLUTION :N//A
Discussion
4.

How many Stereoisomers are formed in following reaction ?

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SOLUTION :
Discussion
5.

How many stereocentre and pseudochirality centre present in the following compound ?

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SOLUTION :
Discussion
6.

how many stereo centers are present in product

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SOLUTION :
Discussion
7.

How many spherical balls of radii 2 cm can be placed completely inside a cubical box of edge = 8 cm?

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ANSWER :8
Discussion
8.

How many species will have multiples of .2. in the following equation after balancing? Balanced equation must contain least integral multiples. CrSCN^(2+) + BrO^(-)+OH^(-) rarr Br^(-)+ NO_(3)^(-1) +CO_(3)^(2-)+SO_(4)^(2-)+CrO_(4)^(2-)+H_2O

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Solution : BALANCED equation is
`2CrSCN^(-) +19BrO^(-) +18 OH^(-) rarr `
`19 Br^(-)+2NO_(3)^(-)2SO_(4)^(2-)+2CrO_(4)^(2-)+9H_2O`
THUS, five species have coefficient equal to 2.
Discussion
9.

How many single and double bond are there in ethene C_(2) H_(4)?

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SOLUTION :In `C_(2) H_(4)` there are one double bond and four SINGLE bond in ETHENE.
one C = C double bond.
four C - H single bond.
Discussion
10.

How many significant figures the following numbers possess? (i) 3.60, (ii) 0.005, (iii) 5.629,(iv) 3.75 xx 10^(9)

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SOLUTION :(i) 3, (ii) 1, (III) 4, (iv) 3
Discussion
11.

How many siliconatomsare present in the atom are present in the anion of a pyrosilicates ?

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ANSWER :2
Discussion
12.

How many significant figures should be present in the answer of the following calculations ? (i) (0.02856 xx 298.15 xx 0.112)/(0.5785) (ii) 5xx5.364 (iii) 0.0125+0.7864+0.0215

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SOLUTION :(i) In MULTIPLICATION and division 3 significant figure PRESENT in 0.112 so, no more than 3 significant figure in answer.
(ii) In multiplication 5 is constant and definite NUMBER so in other value there are four significant figures, so Ans is four.
(iii) In the GIVEN addition the least number of decimal places is 4. So 4 significant figures.
Discussion
13.

How many significant figures should be present in the answer of the following calculations? (i) (0.02856 xx 298.15 xx 0.112)/0.5785, (ii) 5 xx 5.364, (iii) 0.0125 + 0.7864 + 0.0215

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Solution :(i) The least PRECISE term (i.e., 0.112) has 3 significant figures. Hence, the answer should have 3 significant figures.
(ii) 5 is the exact number. The other term, i.e., 5.364 has 4 significant figures. Hence, the answer should have 4 significant figures.
(iii) The answer should have 4 significant figures because the least number of DECIMAL PLACES is 4.
Discussion
14.

How many significant figures should be present in the answer of the following calculations ? (2.5xx1.25xx3.5)/(2.01)

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Solution :Least precise term 2.5 or 3.5 has TWO significant FIGURES. Hence, the ANSWER must have two significant figures.
`(2.5xx1.5xx3.5)/(2.01)=5.4415=5.4`
Discussion
15.

How many significant figures are there in V ?

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SOLUTION :INFINITE NUMBER.
Discussion
16.

How many significant figures are these in Avogadro constant?

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Solution :Avagadro constant `= 6.022xx10^(23)`
Number of SIGNIFICANT FIGURES is 4
Discussion
17.

How many significant figures are present in the following? (i) 0.0025 (ii) 208 (iii) 5005(iv) 126,000 (v) 500.0 (vi) 2.0034

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SOLUTION :(i) 2, (ii) 3, (III) 4, (iv) 3, (V) 4, (vi) 5
Discussion
18.

How many significant figures are present in the following ? (i) 0.0025(ii) 208(iii) 5005 (iv) 126.000(v) 500.0(vi) 2.0034

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SOLUTION :(i) `0.0025 -2`
(ii) `208-3`
(III) `5005-4`
(iv) `126.000-6`
(V) `500.0-4`
(vi) `2.0034-5`
Discussion
19.

How many significant figures are present in 2345?

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2
3
4
5

Answer :C
Discussion
20.

How many significant figures are in 0.2500 g?

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ANSWER :FOUR
Discussion
21.

How many (sigma) sigma bonds are present in P_4O_10 ?

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6
8
18
16

Answer :D
Discussion
22.

How many sigma and pi bonds in the following examples? (a) CH_(3)C -=N(b) CH_(2) = C = CH_(2) (c ) C_(2)H_(6) (d) CH_(2) = CH - CH_(2) - C -= CH (e ) CH_(3)COOH

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SOLUTION :
Discussion
23.

How many sigma bonds are present in ethane ?

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SOLUTION :`H-UNDERSET(H)underset(|)overset(H)overset(|)C-underset(H)underset(|)overset(H)overset(|)C-H`
There are 7s bonds in ethane.
Discussion
24.

How many sigma (sigma) and pi (pi) bonds are present in benzoic acid ?

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`14 SIGMA, 4pi`
`14 sigma, 3 pi`
`15 sigma, 3pi`
`15 sigma, 4pi`

SOLUTION :`pi`-bond : (`3C=C) + (1C=O) = 4`
`sigma`-bond : `(6C-C)+(5C-H) + (2C-O) + (1O-H)+(1C-COOH) = 15`
Discussion
25.

How many sigma and pi bonds are present in the following (a) But-1 ene-3-yne (b) Buta-1, 3-diene ( c) CH_(2) = CH- C -= N (d) Propan-1, 2, 3 diene (e ) 1-butiene and 2-butane

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Solution :(a) `CH_(2)= CH - CH -= CH` (Seven `sigma` and three `pi`)
(B) `CH_(2)= CH- CH= CH_(2)` (Nine `sigma` and TWO `pi`)
(C ) SIX `sigma` and three `pi`
(d) `CH_(2)= C= C= CH_(2)` (seven `sigma` and three `pi`)
(e ) `HC -= C- CH_(2)- CH_(3)` (Nine `sigma` and two `pi`)
Discussion
26.

How many sigma and pi bonds are present in pent-3-ene-1-yne respectively?

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`10sigma, 3PI`
`11 sigma, 2-pi`
`8sigma, 3pi`
`10 sigma, 4PI`

Solution :`HC =C- overset(overset(H)(|))( C)-overset(overset(H)(|))( C)-CH_(3)`
`6 rarr 10, pi rarr 3`
Discussion
27.

How many sigma " and"pibonds are present in HC-=C-CH=CH-CH_(3)?

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`9sigma,4pi`
`10sigma,3pi`
`6sigma,6pi`
`5sigma,5pi`

ANSWER :B
Discussion
28.

How many sigma " and pi bonds are present in each of the following molecules ? CH_(3) - CH_(2) - C^(@) N

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Solution :
`sigma_(C-C) = 2 ""sigma_(C -N) = 1`
`sigma_(C -C) = 2 ""pi_(C-C) = 2`
Discussion
29.

How many sigma " and pi bonds are present in each of the following molecules ? CH_(2) = C = CH_(2)

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Solution :
`sigma_(C-H) = 5 ""pi_(C-N) =2`
`sigma_(C-H) = 4`
Discussion
30.

How many sigma-and -pi-bonds are present in each of the following molecules ? (a) HC -= C CH = CHCH_(3) (b) CH_(2)=C=CHCH_(3)

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SOLUTION :WRITE the COMPLETE STRUCTURAL formulae and count the number of carbon-carbon, carbon-hydrogen sigma-bonds and carbon-carbon pi-bonds :
Discussion
31.

How many sigma and pi bonds are present in each of the following molecules? (a) HC -= C CH= CHCH_(3) (b) CH_(2) = C = CHCH_(3)

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Solution :(a) `H underset(sigma)- C underset(sigma)(-=) C - underset(underset(H)(|))(C )= overset(overset(H)(|))(C )- underset(underset(H)(|))overset(overset(H)(|))(C )-H`
`H overset(sigma)- C underset(sigma)overset(2pi)(-=) C overset(sigma)- underset(underset(H)(sigma|))(C ) underset(pi)overset(sigma)= underset(underset(H)(sigma|))(C )- underset(underset(H)(sigma|))overset(overset(H)(sigma|))(C )overset(sigma)- H`
`{:(pi "bond": C -= C,: "two " pi "bond"),(C= C,: "one " pi "bond"),(,BAR("Total three " pi "bond")):}`
`sigma` bond " `6C - H sigma + 4 C-C sigma`
`:. 10 sigma` bond
In Acyclic hydrocarbon
`C-C sigma` bond = (Total CARBON -1)
`C-H sigma` bond = (No. of total - H)
No. of `pi` bond = (No. of tripal `xx 2`)
= (No.of double bond `xx1` )
No. of `pi` bond `= (("No. H atom according to No. formaula of alkane")-("No. of PRESENT molecule"))/(2)`
(B) `CH_(2)= C = CH - CH_(3)`
Formula: `C_(4)H_(6)`
So, with `6H 6C- H sigma` bond + between 4 carbon `(4-1)= 3 sigma` bond
`:. bar("total " 9 sigma"bond ")`

+ two `pi` bond (becasue of two double bond)
Discussion
32.

How many sigma and Pi bonds are present in CH_(2)=C=CHCH_(3)?

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<P>

SOLUTION :`CH_(2)=C=CHCH_(3)`

`9=sigma` bonds 2 p bonds.
Discussion
33.

How many sigma and pi bonds are present in CH_(2)=C=O

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SOLUTION : `4 SIGMA`-BONDS and `2PI`-bonds
Discussion
34.

how many (sigma) and (pi) bonds are present in buta-1,3-diyne?

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SOLUTION :`UNDERSET("Buta-1,3-diyne")(H-C-=C-C-=C-H)" "SIGMA`-BONDS: 5, `PI`-bonds:4
Discussion
35.

How many sigma and pi bonds are present in an acetylene molecule ?

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Solution :`H-C=C-H` THREE SIGMA BONDS and TWO pi bonds.
Discussion
36.

How many sigma and pi bond are there in propylcyanide?

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`10 sigma, 2pi`
`8 sigma, 2pi`
`10 sigma, 3PI`
`11 sigma, 2pi`

SOLUTION :PROPYL cyanide: `H- underset(underset(H)(|))overset(overset(H)(|))(C )- underset(underset(H)(|))overset(overset(H)(|))(C )- underset(underset(H)(|))overset(overset(H)(|))(C )-C -=N`
Discussion
37.

How many sigma and pi bonds are present in acetophenone ?

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SOLUTION :`{:(8,C-C,sigma-"BOND"),(1,C-O,sigma-"bond"),(8,C-H,sigma-"bond"):}/({:("Total 17 "sigma"bond"),("1C-O"pi-"bond"),(UL("3C-C"pi-"bond of ring")),("Total 4 "pi-" bond"):})`
Discussion
38.

How many Sigma and Pi bonds are Present in (a) C_(2)H_(2) and (b) C_(2)H_(4) ?

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SOLUTION :`5 SIGMA ` and `1 pi` BOND
Discussion
39.

How many sereoisomera are possible for CH_(3)-underset(Br)underset(|)CH-underset(Cl)underset(|)Cl-underset(Br)underset(|)CH-CH_(3)

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SOLUTION :N//A
Discussion
40.

How many series and groups present in Mendelev's periodic table ?

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Solution :7 PERIODS and 8 groups. Every GROUP DIVIDED into TWO other group A and B.
Discussion
41.

How many seconds are there in 7 days?

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Solution :1Day = 24hr, `1 = (24h)/(1day) , 1hr = 60min`,
1 = `(60min)/(1hr) , 1min = 60sec , 1 = (60s)/(1min)`
The unit factors can be multiplied in SERIES in ONE step only.
`7 Day XX (24h)/(1day) xx (60min)/(1min) xx (60s)/(1min) = 7xx24xx60xx60s = 604800s`
Discussion
42.

How manyseconds are there in 2 days ?

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Solution :Here, we know 1 day = 24 HOURS (h)
or `("1 day")/("24h")=1=("24h")/("1 day")`
then 1h = 60 min or `(1h)/("60 min")=1=("60 min")/(1h)`
For CONVERTING 2 DAYS to seconds.
The unit FACTORS can be multiplied in series in one step only as follows :
`"2day"xx(24h)/("1 day")xx("60 min")/("1 h")xx(60s)/("1 min")`
`=2xx24xx60xx60s=1172800s`
Discussion
43.

How many secondary carbons present in the given compound

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ANSWER :5
Discussion
44.

How many resonance structures possible for CO_(3)^(2-)

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SOLUTION :
Discussion
45.

How many reagents are used to identify chromium after oxidation to chromate ion? BaCI_(2),""CaCI_(2), (acidified H_(2)O_(2)-amyl alcohol), AgNO_(3)

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Solution :`BaCI_(2)`, (ACIDIFIED `H_(2)O_(2)`-AMYL alcohol), `AgNO_(3)`
Discussion
46.

How many resonance structures are possible for phenoxide ion

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SOLUTION :
Discussion
47.

How many reagents from the list below would give effervescence when reacted with 1-Pentyne? NaOH(I), CH_3CH_2ONa(II), CH_3CH_2MgBr(III), NaH(IV) , NaNH_2(V), Na(VI), NaHCO_3(VII),[(CH_3)_2CH]_2 Nli(VII), CH_3CH_2Li(IX),C_6H_5Li(X)

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Solution :`CH_3CH_2MgBr (III) ` GIVE ethane GAS . NaH (IV), Na(VI), gives `H_2` gas . `NaNH_2(V)`gives `NH_3` gas . `CH_3CH_2Li(IX)`
Gives ethane gas . `[(CH_3)_2CH]_2NLi and C_6H_5Li` also forms salts but the products `[(CH_3)_2 CH]_2NH and C_6H_6` are liquid at room temperature , no EFFERVESCENCE are observed.
Discussion
48.

How many reactions will proceed through free radical addition mechanism ?

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SOLUTION :Only (III) & (V)
Discussion
49.

How many radial/spherical nodes will be present in the 5f orbital ?

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Solution :No. of radial NODES `= (n -L -1) = 5 - 3 - 1 = 1`
Discussion
50.

How many reactions are correct ?

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ANSWER :3 (I, II, IV)
Discussion