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 one strand of DNA has the sequence 5' -G-G-A-C-T-A-C-T-3', what is the sequence of bases in the complementary strand ?

Answer»

SOLUTION :3.-C-C-T-G-A-T-G-A-5.
2.

If one mole of monoatomic ideal gas expanded from 2 atm to 0.5 atm at 27°C, then the entropy change will be

Answer»

R In 2
4R In 2
3 RIN 2
2R In 2

Answer :1
3.

If one mole of an ideal gas (C_(p.m) = (5)/(2)R) is expanded isothermally at 300 K until it's volume is tripled , then change in entropy of gas is:

Answer»

zero
INFINITY
`(5)/(2)R In 3`
`R In 3`

SOLUTION :N//A
4.

If one mole of ammonia and one mole of hydrogen chloride are mixed in a closed container to form ammonium chloride gas , then

Answer»

`DeltaHltDeltaU`
there is no relationship
`DeltaHgtDeltaU`
`DeltaH=DeltaU`

Solution :`NH_(3(G))+HCl_((g))toNH_(4)Cl_((g))`
`DELTAN=` no . Ofmoles of product - no of moles of REACTANT
`=1-2`
`Deltan=1`
Now , `DeltaH=DeltaE+DeltanRT`
`DeltaH=DeltaE-RTorDeltaE=DeltaH+RT`
`thereforeDeltaEgtDeltaH(DeltaE=DeltaU)`=change in internal energy.
5.

If one mole of AgCZ is dopped with 10^(-5) mole of CaCl_(2) then number of Ag^(+) ions lost from the lattice

Answer»

`10^(-5)`
`6 xx 10^18`
`1.2 xx 10^19`
`3 xx 10^18`

Answer :C
6.

If one mole of AgCl is dopped with 10^(-5)mole of AICI_3, the number of cation vacancies created are

Answer»

`10^(-5)`
`6 XX 10^18`
`12 xx 10^18`
`12 xx 10^19`

ANSWER :C
7.

If onemole monoatmic ideal gas was taken through process AB as shown is figure , then select correcgtoption(s). Given: In 1.5 = 0.4

Answer»

`W_(AB)= - 1496.52 J`
`q_(AB)=5237.82 J`
`DeltaH_(AB) = 3741.3 J`
`DeltaS_(AB) "is + ve"`

Solution :(a)`"y = mx" + C`
`10 = mm xx 300 + C`
`15 = mxx 600+ C`
`5 = 300 m`
`m = (1)/(60), "" c= 5`
`V=(1)/(60) T + 5""w = - int PDeltaV`
`P = 60 R - (300R)/(V)`
` w = -.^(15)int_(10) (60R-(300R)/(V))DV =- 1496.52J`
(b)`DELTAU= q + w or q= DeltaU-w`
`DeltaU= C_(V) DeltaT =374 .13`
`q = 374.13 + 1496.525 = 5237. 82 J`
(c)`Deltah = (5)/(2) xx Rxx 300 `
(d) `DeltaS = + ve`
8.

If one million atoms of silver weight 1.79xx10^(-16)gm the gram atomic mass of silver is:

Answer»

107 g/mol
107.2 g/mol
107.8 g/mol
108.2 g/mol

Answer :C
9.

If one litre of air is passed repeatedly over heated copper and magnesium till no further reduction in volume takes place, the volume finally obtained is

Answer»

800ML
990 ML
10 ml
100 ml

Answer :C
10.

If one first order reaction is completed by 50% in 1.26xx10^(14) second then how much time will be taken by this reaction to complete 100%?

Answer»

`1.26xx10^(15)` SECOND
`2.52xx10^(14)` second
`2.52xx10^(25)`second
INFINITE time

Solution :100% reaction will COMPLETED when it runs for infinite time and hence,time can not be calculated.
11.

If one end of a piece of a metal is heated the other end becomes hot after some time. This is due to

Answer»

ENERGISED ELECTRONS MOVING to the other part of the metal
resistance of the metal
mobility of atoms, in the metal
minor PERTURBATION in the energy of atoms

Solution :It is due to MOVEMENT of energised electrons. `(KE propT)`.
12.

If one end of a piece of a metal is heated, the other end becomes hot after some time. This is due to

Answer»

ENERGISED electrons MOVING to the other part of the metal
Resistance of the metal
Mobility of ATOMS in the metal
Minor perturbation in the energy of atoms

Answer :A
13.

If one cell has standard electrode potential of 0.0295V and n=2 then calculate its equilibrium constant at 298K temperature

Answer»


ANSWER :`K_(C)=1.0xx10^(10)`
14.

Ifon performing theexperiment, 2 . 28 g of (NH_(4))_(2) PbCl_(6) was produced, calculatethe percentage yield of (NH_(4))_(2) Pb Cl_(6)

Answer»

Solution :`% "yield " = ("amount produced experimentally")/("amountfor 100% yield") XX 100`
`= (2 . 28)/( 4 . 56) xx 100 = 50%`
15.

If one atom of hydrogen weighs 1.65 xx 10^(-24)g, then mass of one atom of carbon weighs

Answer»

`1.98 xx 10^(-23) g `
`1.65 xx 10^(-24) g `
`1.37 xx 10^(-25) g `
`1.40 xx 10^(-23) g `

Solution :An atom of carbon is 12 times HEAVIER than an atom of HYDROGEN . THEREFORE , mass of one atom of carbon ` = 1.65 xx 10^(-24) xx 12 = 1.98 xx 10^(-23) g `
16.

If OH-group in lactic acidis replaced by hydrogen atom, which will happened ?

Answer»

OPTICAL ACTIVITY is retained
optical activity is lost
form recemic mixutre
PRODUCE non-superimposable mirror image

Answer :B
17.

If O_(2) gas in bubbled through water at 293 K, how many millimoles of O_(2) gas would dissove in 1 littre of water ? Assume that O_(2) exerts a partial pressure of 0.987 bar and k_(H) for O_(2)=34.86 k bar.

Answer»


Solution :Step I. Calculation of `x_(O_(2))`
`x_(O_(2))=rho_(O_(2))/k_(H)=((0.98"bar"))/((43860"bar"))=2.83xx10^(-5)`
Step II. Calculation os milli-MOLES of `O_(2)`
If N moles os `O_(2)` are present in 1 L of water (or 1000 g of water)
`X_(N_(2))=n/(n+55.5)=n/(55.5)`
`n=X_(N_(2))xx55.5=2.83xx10^(-5)xx55.5`
`=157.06xx10^(-5)mol=157.06xx10^(-2)`milli-moles
=1.57 milli-moles
18.

If observed molar mass of a solute is more than calculated molar mass, then the solute undergoes .............. in the solvent.

Answer»

SOLUTION :ASSOCIATION
19.

If [OH^-] is 1 xx 10^-8 ion/litre.Is pH is:

Answer»

6
7
5
8

Answer :A
20.

If N_(x) is the number of bonding orbitals of an atom and N_y is the number of antibonding orbitals, then the molecule/atom will be stable if

Answer»

`N_x ltN_y`
`N_x = N_y`
`N_x gtN_y`
`N_x leN_y`

ANSWER :C
21.

If n_(t) number of radioatoms are present at time t, the following expression will be a constant

Answer»

`n_(t)//t`
ln `n_(t)//t`
`d ln n_(t)//DT`
`t.n_(t)`

Solution :`- (dn_(t))/(dt) = LAMDA n_(t) RARR - (1)/(n_(1)) (dn_(t))/(dt) = lamda`
`rArr (d)/(dt) (ln, n_(t)) = - lamda`, a CONSTANT
22.

If n_t number of radiatoms are present at time t, the following expression will be a constant.

Answer»

`n_t//t`
`LN n_t//t`
`d ln n_t//dt`
`t cdot n_t`

Solution :`-(dn_t)/(dt) = LAMBDA n_t implies - 1/(n_t) (dn_t)/(dt) = lambda`
`implies d/(dt) (ln n_t) = -lambda`, a constant.
23.

If no catalyst (H^(+)) is present in acid hydrolysis of ester (in above question) then constant K is :

Answer»

`(2.303)/(t)"LOG"(V_(0))/(V_(t)-V_(oo))`
`(2.303)/(t)"log"(V_(oo))/(V_(oo)-V_(t))`
`(2.303)/(t)"log"(V_(0))/(V_(t))`
`(2.303)/(t)"log"(V_(oo))/(V_(t)-V_(oo))`

ANSWER :B
24.

If non ideal solution is prepared by mixing 30 mL CHCl_(3) and 50 mL Acetone, then volume of solution is ……..

Answer»

`GT` 80 ML
`lt` 80 mL
`= 80` mL
`ge` 80 mL

Solution :DUE to formation of H - bond between `CHCl_(3)` and acetone A-B attraction is more than A-A and B-B, so this solution shows negative deviation from Raoult.s law.
Means,`DELTA V_(mix)-ve, Delta H_(mix)=-ve`
So, total volume `= lt` 80 mL.
25.

If NH_4OH is added to the (PtCl_2)^(2-) ion, the complexformed represents:

Answer»

ZERO dipole
Finite dipole
Infinite-dipole
All of the above

Answer :B
26.

If N_(B) is the number of bonding electron and N_(A) is the number of antibonding electrons of a molecules. Then choose the incorrect statement(s) for the relationship , N_(B)gtN_(A)"

Answer»

Molecule may be STABLE or unstable
Molecule may have any integral, frational or zero VALUE of bond order
Molecule is only PARAMAGNETIC species
Molecule does not EXIST

Solution :Molecule may have only integral/ fractional value of bond order
Molecule may or not be paramagnetic
molecule will exist
27.

If NaOH is added to an aqueous solution of zinc ions, a white precipitate appears ad on adding excess NaOH, the precipitate dissolves. In this solution zinc exists in the

Answer»

Cationic part
ANIONIC part
Both in cationic and anionic parts
There is not ZINC in the solution

Solution :`ZN^(2+)+2NaOHtoZn(OH)_(2)+2Na^(+)`
`Zn(OH)_(2)+2NaOHtoNa_(2)ZnO_(2)+2H_(2)O`.
28.

If NaOH is added to an aqueous solution of zinc ions a white precipitate appears and on adding excess of NaOH, the precipitate dissolves. In this solution, zinc exists in the

Answer»

CATIONIC part
Anionic part
Both in the cationic and anionic parts
there is no zinc ION in the SOLUTION

Solution :`Zn^(2+)+2NaOH to Zn(OH)_(2) +2Na^(+)`
`Zn(OH)_(2) +2NaOH to Na_(2)ZnO_(2)+2H_(2)O`
29.

If NaCl is doped with 10^(4) mol % of SrCl_(2) the concentration of cation vacancies will be (N_(A) = 6.02 xx 10^(23) mol^(-1))

Answer»

`6.02 xx10^(16) MOL^(-1)`
`6.02 xx10^(17) mol^(-1)`
`6.02 xx10^(14) mol^(-1)`
`6.02 xx10^(15) mol^(-1)`

Answer :B
30.

If NaCl is doped with 10^(-4) mol % of SrCl_(2) , the concentration of cation vacancies will be ( N_(A) = 6.022 xx 10^(23) mol^(-1))

Answer»

`6.02 xx 10^(18) MOL^(-1)`
`6.02 xx 10^(17) mol^(-1)`
`6.02 xx 10^(14) mol^(-1)`
`6.02 xx 10^(15) mol^(-1)`

Solution :ONE cation of `Sr^(2+)` would create one cation vacancy in NaCl. Therefore , the number of cation vacancies created in the LATTICE of NaCl is equal to the number of divalent `Sr^(2+)` ions added.
No. of moles of cationic vacancies ` = ( 10^(-4))/( 10^(2)) = 10^(-6)` mol
No. of cation vacancies
` = 10^(-6) xx 6.02 xx 10^(23) = 6.02 xx 10^(17)`
31.

If NaCl is doped with 10^(-3) mole percent SrCl_(2), what will be the concentration of cation vacancies ? (N_(A) = 6.02 xx 10^(23) mol^(-1))

Answer»

Solution :Every `Sr^(2+)` ion causes ONE cation vacancy (because two `Na^(+)` ions are REPLACED by one `Sr^(2+)`)
Therefore, introduction of `10^(-3)` moles of `SrCl_(2)` per 100 moles of NaCl would introduce `10^(-3)` mole cation VACANCIES in 100 moles of NaCl.
No. of vacancies per mole of NaCl
`= (10^(-3))/(10000) xx 6.02 xx 10^(23) = 6.02 xx 10^(18)` vacancies.
32.

If NaCl is doped with 10^(-3) mol % SrCl_2, what is the concentration of cation vacancies?

Answer»

Solution :Doping of NaCl with `10^(-3) mol % SrCl_2`, means that 100 moles of NaCl are doped with `10^(-3)` mol of `SrCl_2`.
`:.` 1 mole of NaCl is doped with `SrCl_2 =(10^(-3))/(100) = 10^(-5)` mol
As each `SR^(2+)` ION introduces one cation vacancy, THEREFORE concentration of cation vacancies = `10^(-5) mol//mol` of NaCl = `10^(-5) xx 6.02 xx 10^(23)` cation vacancies `mol^(-1)` = `6.02 xx 10^(18)` cation vacancies `mol^(-1)`
33.

If NaCl is doped with 10^(-3) mol % of SrCl_(2) what is the concentration of cation vacancy?

Answer»

Solution :ONE cation of `SR^(2+)` would create one cation vacancy in NaCl.
`:.`Concentration of cation vacancy on being doped with `10^(-3)` mol% `SrCl_(2)`
`= 10 ^(-3) mol%`
`=(10 ^(-3))/(100) "mol"`
`=(10 ^(-3))/(100) XX 6.02 xx 10^(23)`
cation vacancies PER mole
`= 6.02 xx10^(18)`cation vacancies per mole.
34.

If NaCl is doped with 10^(-3) mol % of SrCl_2, what is the concentration of cation vacancies ?

Answer»

SOLUTION :Let moles of NaCl in the crystal = 100
Moles of `SrCl_2` doped = `10^(-3)`
`therefore` No. of `NA^(+)` ions replaced by each `SR^(2+)` ions = 1
No. of CATIONIC vacancies formed by `Sr^(2+)` ions = 1
`therefore` Number of cationic vacancies = `10^(-3)`
formed by `10^(-3)` mol `SrCl_2`
`therefore` Vacancy per mole of `NaCl =(10^(-3))/(100) = 10^(-5)`
`therefore` Number of vacancies per mole of NaCl
` = 6.022 xx 10^23 X 10^(-5)`
` = 6.022 xx 10^18`.
35.

If NaCl is doped with 10^(-3) mol % of SrCl_(2), what is the concentration of cation vacancies ?

Answer»

Solution :Let us take one MOLE of `NaCl`. For every `Sr^(2+)` ion INTRODUCED, one `Na^(+)` ion will be removed and one vacancy will be created.
Amount of `SrCl_(2)=(10^(-3))/(100)" moles"`
`=10^(-5)" moles "=10^(-5)xx6.02xx10^(23)" molecules "=6.02xx10^(18)" molecules"`
As each `Sr^(2+)` ion intrduced creates one cation vacancy, CONCENTRATION of cation vacancies `=6.02xx10^(18)` PER mole.
36.

If NaCl is doped with 10^(-2) mol % SrCl_2, what is the concentration of cation vacancies?

Answer»


SOLUTION :Doping of NaCl with `10^(-2)` mole % of `SrCl_2` means that 100 MOLES of NaCl are doped with 10 mole of `SrCl_2`.
`:.` 1 mole of NaCl is doped with `SrCl_2=(10^(-2))/(100)= 10^(-4)` MOL
As each `Sr^(2+)` ion introduces one cation vacancy, therefore, concentration of cation vacancies = `10^(-4) mol//mol` of NaCl = `10^(-4) xx 6.02 xx 10^(23)` cation vacancies `mol^(-1) = 6.02 xx 10^(19)` cation vacancies `mol^(-1)`.
37.

If NaCl crystals are doped with 2 xx 10^(-3) mol per cent of SrCl_(2), calculate the cation vacancies per mole.

Answer»

Solution :Doping of `NaCl` with `2xx10^(-3)` mol per cent of `SrCl_(2)` means 100 MOLES of `NaCl` are dropped with `2xx10^(-3)` moles of `SrCl_(2)` or 1 mole of `NaCl` is doped with `=2xx10^(-5)` mole of `SrCl_(2)`.
Each `Sr^(2+)` will occupy the place of `Na^(+)` and displace one `Na^(+)` from crystal lattice to create cation vacancies.
Cation vacancies = Number of `Sr^(2+)` ion added
`=2xx10^(-5)mol=2xx10^(-5)xx6.023xx10^(23)=12.046xx10^(18)=1.2046xx10^(19)mol^(-1)`.
38.

If NaCl is doped with 10^(-2) mol percentage of strontium chloride, what is the concentration of cation vacancy ?

Answer»

Solution :We KNOW that two `Na^(+)`ions are replaced by each of the `Sr^(2+)` ions while `SrCl_(2)` is doped with NaCl. But in this case, only one lattice POINT is occupied by each of the `Sr^(2+)` ions and PRODUCE one cation vacancy. Here `10^(-2)` mole of `SrCI_(2)` is doped with 100 moles of NaCl. Thus, cation vacancies produced by NaCl = `10^(-2)` mol. Since, 100 moles of NaCl produces cation vacancies after doping = `10^(-2)` mol.
Therefore, 1 mole of NaCl will produce cation vacancies after doping
`=(10^(-2))/(100)=10^(-4)"mol"`
`therefore"Total cationic vacanices,"`
`=10^(-4)xx"Avogadro.s NUMBER"`
`=10^(-4)xx6.023xx10^(23)`
`=6.023xx10^(19)" vacancies"`
39.

If Na_2SO_3 is left open in air, we get:

Answer»

`Na_2S`
`Na_2SO_4`
`Na_2HSO_4`
`Na_2HSO_3`

ANSWER :B
40.

If N_A is Avogadro's number, then the number of hydrogen atoms in one g-equivalent of hydrogen is :

Answer»

`N_A`
`N_A//2`
`N_A//4`
`2N_A`

ANSWER :B
41.

If Na^(+) ion and S^(2-) ion is larger than Cl^(-) ion, which of the following will b least soluble in water

Answer»

`MgS`
`NACL`
`Na_(2)S`
`MgCl_(2)`

Solution :`UNDERSET("Solubility DECREASING order")OVERSET(NaCl gt Mg Cl_(2) gt Na_(2)S gt MgS)to`
42.

If n_A and n_Brepresent the number of moles of components A and B, the mole fraction of A(x_A) is given by

Answer»

`n_A//n_B`
`n_B // n_A`
`n_A // n_A + n_B`
`n_A + n_B // n_A`

ANSWER :C
43.

If n=6, the correct sequence for filling of electrons will be:

Answer»

`NSTO(N-2)F to(n-1)d tonp`
`nsto(n-1)d to (n-2)f to np`
`nsto(n-2)f to n p to (n-1)d`
`nstonpto(n-1)d to (n-2)f`

Solution :For n=6
`6s t o4f to 5d to 6P`
44.

If N_(2) gas is bubbled through water at 293 K, how many millimoles of N_(2) gas would dissolve in 1 litre of water ? Assume that N_(2) exerts a partial pressure of 0.987 bar. Given that Henry's law constant for N_(2) at 293 K is 76.48 k bar.

Answer»

Solution :The solubility of gas is related to the mole fraction in aqueous solution. The mole fraction of the gas in the solution is calculated by applying Henry.s law. Thus :
x (Nitrogen) `= ("p (nitrogen)")/(K_(H))`
`=(0.987" bar")/(76480" bar")=1.29xx10^(-5)`
As 1 LITRE of water contains 55.5 MOL of it, therefore if n represents number of MOLES of `N_(2)` in solution,
x(Nitrogen) `= ("n mol")/(n mol +55.5 mol)`
`= (n)/(55.5)=1.29xx10^(-5)`
(n in denominator is neglected as it is `LT lt 55.5`)
Thus, `n = 1.29xx10^(-5)xx55.5 mol = 7.16xx10^(-4)` mol
`= (7.16xx10^(-4)mol xx 1000 m mol)/(1 mol)`
= 0.716 m mol
45.

If N_(2) gas is bubbled through water at 293 K, how many of millimoles of N_(2) gas would dissolve in 1 litre of water 7 Assume that N_(1) exerls a partial pressure of 0.987 bar. Given that Henry's law constant for N_(2) at 293 K is 76.48 K bar.

Answer»

Solution :ACCORDING to Henry.s LAW
x(Nitrogen ) = `(p("Nitrogen"))/(K_(H))`
= `(0.987)/(74,480("bar"))`
= `1.29 xx 10^(-5)`
As 1 litre of water contains 55.5 mole of it, therefore if n represents number of moles of `N_(2)` in solution.
x (Nitrogen ) = `(n"mole")/("n mole + 55.5 mol")`
= `(n)/(55.5) = 1.29 xx 10^(-5) = 1.29 xx 10^(-5)`
(n in denominator is neglecti!d as it is `lt lt `55.5)
So, n= 1.29` xx 10^(-5) xx 55.5 `mol
= `7.16 xx 10^(-4)` mol
`= (7.16 xx 10^(-4)"mol" xx 1000 "mol")/(1 "mol")`
= 0.716 m/mol
46.

If N_2 gas is bubbled through water at 293 K , how many millimoles of N_2 gas would dissolve in 1 litre of water? Assume that N_2 exerts a partial pressure of 0.987 bar. Given that Henry’s law constant for N_2 at 293 K is 76.48 k bar.

Answer»


ANSWER :0.716 MOL
47.

If N_(2) gas is bubbled through water at 293 K, how many millimoles of N_(2) gas would dissolve in 1 litre of water ? Assume that N_(2) exerts a partial pressure of 0.987 bar. Given that Henry's law constant for N_(2) at 298 K is 76.48 kbar.

Answer»

<P>

Solution :`"According to Henry's law, "p_(N_(2))=K_(H)xxx_(N_(2)), thereforex_(N_(2))=(p_(N_(2)))/(K_(H))=("0.987 bar")/("76480 bar")=1.29xx10^(-5)`
If N moles of `N_(2)` are prsent in 1 L of water (i.e., 55.5 moles), `x_(N_(2))=(n)/(n+55.5)~=(n)/(55.5)("as "ltlt 55.5)`
`therefore""(n)/(55.5)=1.29xx10^(-5)"or"n=1.29xx10^(-5) xx 55.5" moles"=71.595xx10^(-5)" moles = 0.716 MILLIMOLES"`
48.

If N_2 + 3H_2 hArr 2NH_3 has equilibrium constant K and 2N_2 + 6H_2 hArr 4NH_3 has equilibrium constant k', then k' =

Answer»

`K^2`
sqrtK
1/sqrtK
1/K^2

Answer :A
49.

If N_1,N_2,N_3…….. Are the number of molecules with molecular masses M_1,M_2,M_3………. Respectively, than mass average molecular mass is expressed:

Answer»

`(sumN_iM_i^2)/(sumN_iM_i)`
`(sumN_iM_i)/(sumN_i)`
`(sumM_i^2)/(sumN_i)`
`(sumN_iM_i^2)/(sumM_i)`

ANSWER :A
50.

If n_(1) is the number of radio-atoms present at tiem 't' the following expression will be a constant,

Answer»

`(n_(t))/(t)`
`(In n_(t))/(t)`
`(d In n_(t))/(dt)`
`t n_(t)`

SOLUTION :`(d n_(t))/(dt) = LAMBDA n_(t)`
`(1)/(n_(t)) (d n_(t))/(dt) = lambda`
`(d)/(dt) (l_(n) n_(t)) = -lambda` constant 1