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.

If 50 calorie are added to a system and system does work of 30 calorie on surroundings, the change in internal energy of system is:

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20 cal
50 cal
40 cal
30 cal

Answer :A
2.

if 50 atoms of carbon reacts with 200 molecules of oxygen, find out the correct statement(s)

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`O_2` is the limiting reagent
`50` MOLECULES of` CO_2` are formed
`100` molecules of` CO_2` are formed
Both (1) & (2)

ANSWER :B
3.

If 50 calorie are added to a system and system does wark of 30 calorie on surroundings, the change in internal energy of system is

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30 cal
50 cal
40 cal
20 cal

Answer :D
4.

If 5% sugar solution is isotomic with 1% solution of unknown substance, then find out molecular mass of unknown substance.

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ANSWER :68.4 gm/mol
5.

If 5 liters of H_(2)O_(2) produce 50 liters of O_(2) at NTP , H_(2) O_(2) is

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`'50V'`
`'10V'`
`'5V'`
`'250 V'`

ANSWER :B
6.

If 4g of O_(2) diffuse through a very narrow hole, how much H_(2) would have diffused under identical conditions ?

Answer»

1g
`1//4g`
`16G`
64g

Solution :`( 4g//t)/(X//t) = SQRT((2)/( 32))`
( x is the AMOUNT of `H_(2)` diffused and t is the time )
`( 4)/( x) = sqrt((1)/( 16)) = ( 1)/( 4)`
7.

If 4.5 gm Aluminium completely reacts with 4gm of oxygen. Then what will be empirical formula of aluminium oxide.

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`Al_(2)O`
`Al_(2)O_(3)`
`AlO_(2)`
`AIO`

SOLUTION :`Al+O_(2)rarrAl_(X)O_(y)`
`n_(Al)=(4.5)/(27)=(1)/(6) n_(o_(2))=(4)/(52)=(1)/(8)(n_(Al))/(n_(o))=(1)/(6)xx(4)/(1)=(2)/(3)`
`n_(o)=2xxn_(o_(2))=(1)/(4) "FORMULA"=Al_(2)O_(3)`
8.

If 400 gm radioactive Iodine is taken initially. Then calculate the amount the ""(53)I^(128)(t_((1)/(2))="25 min") left after 75 minutes

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ANSWER :50
9.

If 4-methyl-2-pentene is refluxed with dilute sulphuric acid, hydration reaction takes place.On principle, how many different alcohols would be formed ?

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ANSWER :5
10.

If 4 g of NaOH dissolved in 36 g of H_(2)O, calcualte the mole fraction of each component in the solution. Also, determine the molarity of solution (specific gravity of solution is "1 g mL"^(-1))

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Solution :`"4 g NAOH"=(4)/(40)"mole"="0.1 mole"`
`"36 g "H_(2)O=(36)/(18)"mole = 2 mole"`
`THEREFORE " Mole fraction of "H_(2)P=1-0.047=0.953(or(2)/(2+0.1)=0.95)`
`"Total mass of solution "="Mass of solvent "+"Mass of solution"=36+4g=40g`
`"Volume of solution"=("Mass")/("Sp. gravity")=("40 g")/("1 g mL"^(-1))=40mL=0.040L`
`"MOLARITY of solution "=("Moles of solute")/("Volume of solution in L")=("0.1 mole")/("0.040 L")=2.5M`
11.

If 36 g. of Al is deposited at the cathode, the number of moles of electrons used is

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1
2
3
4

Answer :D
12.

If 340 g of mixture N_2 and H_2 in the correct raito gave a 20% yield of NH_3. The mass produced would be:

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16 G
17 g
20 g
68g

Answer :D
13.

If ‘I’ is the intensity of absorbed light and C is the concentration of AB for the photochemical processthe rate of formation of A + hv to AB^(**) is directly proportional to :

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C
I
`I^2`
`CI`

ANSWER :B
14.

If 32 g of O_(2)contain 6 022 xx 10^23 molecules at NTP then 32 g of S, under conditions, will contain,

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`6.022 XX 10^(23)` S
`3.011 xx 10^(23)` S
`12.044 xx 10^(23) S`
`1 xx 10^(23) S`

ANSWER :A
15.

If 30mL of H_(2) and 20mL of O_(2) react to form form water, what is left at the end of the reaction?

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10mL of `H_(2)`
5 ML of `H_(2)`
10mL of `O_(2)`
5 mL of `O_(2)`

ANSWER :A
16.

If 30mL of H_(2) and 20mL of O_(2), reacts to form H_(2)O, what is left at the end of the reaction?

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10mL of `H_(2)`
5ML of `H_(2)`
10mL of `O_(2)`
5mL of `O_(2)`

SOLUTION :`H_(2) (G) +(1)/(2) O_(2)(g) to H_(2)O(g)`
`{:(,"Initially", 30, 20,0),(,"After the reaction",0,(20-15),30):}`
17.

If 3.01xx10^(20) molecules of H_(2)SO_(4) are removed from 98mg of H_(2)SO_(4). Then number of moles of H_(2)SO_(4) left are:

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`0.1xx10^(-3)` mol
`0.5xx10^(-3)` mol
`1.66xx10^(-3)` mol
`9.95xx10^(-2)` mol

Solution :Removed number of moles of `H_(2)SO_(4)=(3.01xx10^(20))/(6.02xx10^(23))`
`=5xx10^(-4)`
`=0.5xx10^(-3)`
Initial number of moles of `H_(2)SO_(4)=(0.098)/(98)=0.001=10^(-3)`
REMAINING moles of `H_(2)SO_(4)=10^(-3)-0.5xx10^(-3)=0.5xx10^(-3)`
18.

If 30g of a solute of molecular weight 154 is dissolved in 250g of benzene, what will be the boiling point of the resulting solution under atmospheric pressure . The molal boiling point elevation constant for benzene is 2.61^(@)C.m^(-1) and the boiling point of pure benzene is 80.1^(@)C

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Solution :Suppose the elevation in B.p. is `DeltaT_(b)`
Molality `=(DeltaT_(b))/(K_(b))=(DeltaT_(b))/(2.61)` …………(Eqn . 8)
Moles of solute `=(30)/(154)`
`:.` molality `=(30)/(154)xx(1000)/(250)` moles / `1000g` of solvent
Thus, `(DeltaT_(b))/(2.61)=(30)/(154)xx(1000)/(250)`
`DeltaT_(b)=2^(@)`
Thus the b.p. of the resulting solution is `80.1+2=82.1^(@)C`
19.

If 30% of an organism's DNA is thymine, then :

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70% is purine
20% is guanine
30% is adenine
Both (B) and (C ) are correct

Answer :D
20.

If 3.01 xx 10^(28) molecules are removed from 98 mg of H_2SO_4, then number of moles of H_2SO_4 left are

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`0.5 xx 10^(-3)` MOL
`0.1 xx 10^(-3)` mol
`9.95 xx 10^(-2)` mol
`1.66 xx 10^(-3)` mol

Solution :`"No. of MOLES" H_(2)SO_(4) "in" 98 mg=(98 xx 10^(-3))/(98)`
`=1 xx 10^(-3)`
No. of moles of `3.01 xx 10^(20)` molecules of `H_(2)SO_(4)`
`=(3.01 xx 10^(20))/(6.02 xx 10^(23))=(1)/(2) xx 10^(-3)`
`"Moles of" H_(2)SO_(4) "left"=(1 xx 10^(-3)-0.5 xx 10^(-3))`
`=0.5 xx 10^(-3)`
21.

If 30 ml of H_(2) and 20ml of O_(2) reacts to form water, what is left at the end of the reaction

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10 ml of `H_(2)`
5 ml of `H_(2)`
10 ml of `O_(2)`
5 ml of `O_(2)`

Solution :`H_(2)+(1)/(2)O_(2)toH_(2)O`
1 mole `(1)/(2)` mole 1 mole
1 VOLUME `(1)/(2)` volume
1 ml `H_(2)` REACTS with `(1)/(2)`ml `O_(2)`
30 ml of `H_(2)` reacts with `=(1)/(2)xx30=15ml" "O_(2)`
(20-15)=50ml of `O_(2)` will left at the end of the reaction.
22.

If 30 ml of H_(2) and 20 ml of O_(2) react to form water, what is left at the end of the reaction?

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`"10 ML of "H_(2)`
`"5 ml of "H_(2)`
`"10 ml of "O_(2)`
`"5 ml of "O_(2)`

Solution :`UNDERSET("2 ml")(2H_(2))+underset("1 ml")(O_(2))rarr2H_(2)O`
`"2 ml of "H_(2)" REACT with 1 ml of "O_(2)." Hence, 30 ml of "H_(2)" will react with 15 ml of "O_(2)`
23.

If 30 mL of H_(2) and 20 mL of O_(2) reacts to form water, what is left at the end of the reaction?

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10 mL of `H_(2)`
5 mL of `H_(2)`
10 mL of `O_(2)`
5 mL of `O_(2)`

Solution :`UNDERSET(2vol)(2H_(2))+underset(1vol)(O_(2))to2H_(2)O`
2 mole of `H_(2)` reacts with 1 vol of `O_(2)` to give water. Therefore, 30 mL of `H_(2)` will reacts with 15 mL of `O_(2)` to give water. Here, `H_(2)` is the LIMITING REACTANT.
Volume of `O_(2)` left unreacted = 20-15=5 mL
24.

If 30% of a first order reaction is completed in 12 mins, what percentage will be completed in 65.33 mins?

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Solution :Give data : Time taken for COMPLETION of 30% of the reaction = 12 mins.
a = 100 , x = 30 , a - x = 70 and t = 12 min
Formula : `K =(2.303)/(t)"log"(a)/(a-x)`
Solution : For a first order reaction,
`=(2.303)/(12)"log"(100)/(70)`
`=(2.303)/(12)xx0.1.549=0.02972 "min"^(-1)`
`k=2.97xx10^(-2)"min"^(-1)`
If t = 65.33 minutes, x = ?
`k=(2.303)/(65.33)"log"(100)/(100-x)`
`0.02972 = (2.303)/(65.33)"log"(100)/(100-x)`
`"log"(100)/(100-x)=(0.02972xx65.33)/(2.303)=0.8430`
`(100)/(100-x)` = Antilog of 0.8430
`100 = 6.966 (100 -x)`
`100 = 696.6-6.966 x`
`-6.966 x = 100 - 696.6=596.6`
`x=(596.6)/(6.966)=85.62%`
The reaction completed in 65.33 minutes
25.

If 30 ml of H_2and 20 ml of O_2react to formwater, what is left at the end of the reaction ?

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10 ml of `H_2`
5 ml of `H_2`
10 ml of `O_2`
5 ml of `O_2`

Solution :`underset("2vol")(2H_2) + underset("1 vol")(O_2) to 3H_2O`
2 vol. of `H_2` react with 1 vol of `O_2` to give WATER
` therefore ` 30 ml of `H_2` will react with 15 ml of `O_2`
Hence of `H_2` is a limiting REACTANT
vol of `O_2` left unreacted = 20 - 15 = 5 ml
26.

If 3 gm of glucose (mol. wt. 180) is dissolved in 60 gm of water at 15^(@)C. Then the osmotic pressure of this solution will be

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0.34 ATM
0.65 atm
6.57 atm
5.57 atm

SOLUTION :`pi=CRT =(3xx1000)/(180xx60)xx0.0821xx288=6.56` atm.
27.

If 3/4 quantity of a radioactive element disintegrates in two hours, its half-life would be

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1 hours
45 minutes
30 minutes
15 minutes

Solution :`N = (25)/(100) N_(0)` (at t = 2 HR)
Thus `t = (2.303)/(0.693) XX t_(1//2) "log"(N_(0))/(N)`
28.

If 3//4 quantity of a radioactive element disintegrates in two hours, its half life would be

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1 hours
45m
30m
15m

Answer :A
29.

If 2L of Cl_(2) gas and 2L of ClF_(3) gas react to form 6L of a pure gaseous compound at the same conditions of temperature and pressure, what is the molecular formula of the compound formed?

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`ClF`
`Cl_(2)F_(2)`
`Cl_(3)F_(3)`
`Cl_(2)F_(5)`

ANSWER :A
30.

If 2.7 gm aluminum metal is deposited on electrodes when two different electrolytic cell having molten Cu(NO_(3))_(2) and Al(NO_(3))_(3) respectively are arranged in series, then how much copper metal is produced ? (Cu=63.5,Al=27.0" gm "mol^(-1)).

Answer»

9.525 gm
31.75 gm
63.5 gm
190.5 gm

Solution :`AL^(3+)+3e^(-) to Al`
So, 3 F electricity GIVES 27 gm of Al, but Al is produced only 2.7 gm
So, FARADAY `=(2.7)/(27)xx3=0.3` Faraday
Reaction : `Cu^(2+)+2E^(-) to Cu`
So 2 F electricity gives 63.5 gm of Cu
So, 0.3 F electricity gives `=(0.3xx63.5)/(2)`
`=9.525gm` Cu
31.

If 250 ml of 0.25 M NaCl solution is diluted with water to voluem of 500 ml, the new concentration of the solution is :

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0.167 M
0.125 M
0.50 M
0.0625 M

Solution :`M_(1)V_(1)=M_(2)V_(2)`
`0.25 M xx 250 ML M_(2)xx500ml`
`:.M_(2)=(0.25xx250)/(500)=0.125M`
32.

If 25 gram of Na_(2)SO_(4) is dissolved in 10^(3) kilogram solution, then concentration will be …….

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25 ppm
0.25 ppm
250 ppm
2.5 ppm

SOLUTION :ppm `= (0.025)/(10^(3))xx10^(6)=25` ppm.
33.

If 224 ml of a triatomic gas has a mass of 1 g at N.T.P., then the mass of one atom is :

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`9.3 xx 10^(-23) G `
`2.08 xx 10^(-23) g`
`5.53 xx 10^(-23) g `
`9.62 xx 10^(-23) g `

Solution :224 ml of gas weigh = 1g
22400 ml of gas weigh
` = (1)/(224) xx 22400= 100 g `
` THEREFORE ` molecular mass of gas= 100
mass of one molecule ` = (100)/(6.02 xx 10^23)`
mass of atom ` = (100)/(6.02 xx 10^23) xx 1/3 ` (triatomic gas)
= `5.53 xx 10^(-23) g `
34.

If 22.4 ml of a triatomic gas has a mass of 0.048 gat 273K and 1 atm pressure, then the mass of one atom is:

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`7.9 xx 10^(-23) g `
`2.6 xx 10^(-23) g `
`2.4 xx 10^(-22) g `
`2.4 xx 10^(-23) g `

Solution :22400 ml of gas weight
` = (0.048)/(22.4) xx 22400 = 48 g `
` therefore ` 1 MOL of gas = 48 g
Mass of ONE atom
`= (48)/(3 xx 6.02 xx 10^23) = 2.6 xx 10^(-23) g `
35.

If 2.0g of a radioactive isotope has a half-life of 20 hr, the half-life of 0.5 g of the same substance is

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20 hr
80 hr
5 hr
10 hr

Solution :Half-life PERIOD is a CHARACTERISTIC of RADIOACTIVE ISOTOPE which is independent of initial concentration.
36.

If 201 persons are sitting in a row AB and if we release NO_(2) (laughing gas) from the side A and tear gas (molecular weight - 176) from side B, then which person will have a tendency to laugh and weep simultaneously?

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`151^(ST)` from A
`67^(TH)` from A
`134^(th)` from A
`134^(th)` from B

Answer :C
37.

If 200ml of 0.2M HgCl_(2) solution is added to 800ml of 0.5M Kl (100% dissociated) solution. Assuming that the following complex formation taken place to 100% extent.

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Solution :`{:(HgCl_(2),+,4KI,rarr,K[HgI_(4)],+,2KCl.),(40,,400,,0,,0),(0,,400-160,,40,,80),(,,(240)/(1000),,(40)/(1000),,(80)/(1000)):}`
`PI=(i_(1)C_(1)+i_(2)C_(2)+i_(3)C_(3))RT`.
`=(0.24xx2+3xx0.04+0.08xx2)0.082xx300.=18.69` atm.
Other METHOD :
`{:(HgCl_(2),+,4KI,hArr,K[HgI_(4)],+,2KCl.),(40,,400,,0,,0),(0,,400-160,,40,,80),(,,(240)/(1000),,(40)/(1000),,(80)/(1000)):}`
`pi=(i_(1)C_(1)+C_(2)+i_(3)C_(3))RT`.
`=(0.24xx2+xx0.04+0.08xx2)0.082xx300.=18.69` atm.
38.

If 200 ml of 0.1 MH_2SO_4 salution is mixed with 200 ml of 0.15 M NaOH solution then heat evolve during the neutralization process is

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411 cal
548 cal
959 cal
822 cal

Answer :A
39.

If 20.0 g of CaCO_(3) is treated with 20.0 g of HCl, how many grams of CO_(2) will be produced ?

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Solution :`UNDERSET(40+12+3xx16=100g)(CaCO_(3))+underset(2(1+35.5)=73g)(2HCl)rarrCaCl_(2)+H_(2)O+underset(12+2xx16=44g.)(CO_(2))`
Here, `CaCO_(3)` will be the limiting reactant.
40.

If 20% nitrogen is present in a compound its molecular weight will be ,

Answer»

0.144
28
100
140

Answer :D
41.

If "20.0 g mL"^(-1) of "1.0 M CaCl"_(2) and "60.0 cm"^(3) of "0.20 M CaCl"_(2) are mixed, what will be the molarity of the final solution?

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SOLUTION :`M_(1)V_(1)+M_(2)V_(2)=M_(3)V_(3)" ,"1xx20 +0.2 xx60=M_(3)(20+60)or M_(3)=(32)/(80)=0.40M`
42.

If 20.0 g of CaCO_3is treated with 200 g of HCI, how many grams of CO_2can be obtained according to the following reaction : CaCO_3(s) + 2HCl(aq)toCaCl_2(aq) + H_2O (l) + CO_2(g)

Answer»

8.80 G
27.4 g
4.20 g
13.7 g

Solution :`CaCO_3 `is the limiting REAGENT
100 g of `CaCO_3` produces `CO_2 = 44g `
20g of `CaCO_3` will GIVE `CO_2 = 44/100 xx 20`
= 8.8 g
43.

If 20% nitrogen is present in a compound, its minimum molecular weight can be:

Answer»

144
70
100
140

Answer :B
44.

If 20 ml of0.5M Na_(2).SO_(4) is mixed with 50ml of 0.2M H_(2)SO_(4) & 30 ml of 0.4M Al_(2)(SO_(4))_(3) solution. Calculate [Na^(+)],[H^(+)].[SO_(4^(2-))],[Al^(3+)]. [Assuming 100% dissociation]

Answer»

Solution :Molarity`=("moles")/("VOLUME")=10M`. Moles of `Na_(2)SO_(4)`
`rArr20m`. Moles of `Na^(+)`
(i) `therefore[Na^(+)]=(20)/(100)=0.2M`
(ii) `[H^(+)]=?`
`10m`. Moles `H_(2)SO_(4)`
20M. Moles `H^(+)`
`[H^(+)]=(20)/(100)=0.2M`
(iii) `[SO_(4)^(2-)]=(10+10+36)/(100)=(56)/(100)=0.56M`
(iv) `[Al^(3+)]=(24)/(100)=0.24M`
`rarr` Derive a relationship between molarity of a solution in which `w GM` of solute of molar MASS `M g//mol` is dissolved in ` W g` solvent `&` density of resulting solution`=d' g//ml`.
say `1 L` solution taken,
mass of `1 lit` solution `=(1000 d) g`
moles of solute `=("molarity") x m`
`therefore=(("molarity")xx1000)/(1000d-"molarity"xxM.Wt)` [Where no, of moles of solute `= "molarity")`
45.

If 20 g. of sodium hydroxide is dissolved in 1 dm^(3) of water, the molarity of the solution will be

Answer»

0.5
0.25
0.1
0.2

Solution :`"Molarity"= "MASS"/("MOLAR mass" xx DM^(3))=20/(40 xx 6)=0.5`
46.

If 20 ml of 0.25N strong acid and 30 ml of 0.2 N of strong base are mixed, then the resulting solution is

Answer»

0.25 N basic
0.2 N acidic
0.25 N acidic
0.2 N basic

Solution :`V_(1)=20ML,N_(1)=0.25N,V_(2)=30ml,N_(2)=0.2N`
`thereforeN=(N_(1)V_(1)+N_(2)V_(2))/(V_(1)+V_(2))=(20(0.25)+30(0.2))/(20+30)`
`=(5+6)/(50)=(11)/(50)=0.2N` basic.
47.

If 20 ml of methane (CH_4) is burnt using 50 ml of oxygen. The volume of the gases left after cooling to room temperature will be:

Answer»

60 ml
70 ml
30 ml
50 ml

Answer :C
48.

If 20 cc of methane in burnt using 50 cc of oxygen, the volume of the gases left after cooling to room temperature is

Answer»

60 cc
70 cc
30 cc
50 cc

Answer :C
49.

If 2 moles of MnO_(4)^(-) completely oxidizes 2.5 moles of M^(+), where the MnO_(4)^(-) reduces to Mn^(2+), then the product M^(+) is

Answer»

`MO_(3)^(-)`
`MO_(2)`
`MO_(4)^(-)`
`M_(2)O_(2)`

SOLUTION :N/A
50.

If 2 faraday current is pass through CuSO_(4) solution then find out how much copper can be deposited on cathode ? [Cu=63.5 gm "mole"^(-1)]

Answer»

0 gm
2 gm
63.5 gm
127 gm

Solution :`CuSO_(4)toCu_((aq))^(2+)+SO_(4(aq))^(2-)`. . . Ionization
`Cu_((aq))^(2+)+2E^(-) to Cu_((S))` . . . (Cathodic reduction)
2 mole `e^(-) to ` 1 MOL COPPER
So 2F current produce 63.5 gm copper