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.

Urea is prepared by the reaction between ammonia and carbon dioxide.2NH_(3_((g)))+CO_(2_((g)))rarr(NH_(4))_(2)CO_(aq)+H_(2)O_((l))In one process, 637.2 g of NH_(3)are allowed to react with 1142 g of CO_(2)(a) Which of the two reactants is the limiting reagent? 2NH_(3_((g)))+CO_(2_((g)))rarr(NH_(4))_(2)CO_(aq)+H_(2)O_((l))(b) Calculate the mass of (NH_(4))_(2)CO formed. 2NH_(3_((g)))+CO_(2_((g)))rarr(NH_(4))_(2)CO_(aq)+H_(2)O_((l))(c) How much of the excess reagent in grams is left at the end of the reaction?

Answer»

Solution :(a) `2NH_(3_((g))) + CO_(2((g))) rarr (NH_(4))_(2)CO_(aq) + H_(2)O_((l))`
No. of moles of ammonia =`637.3/17` = 37.45 MOLE
No. of moles of `CO_(2)` =`1142/44`=25.95 moles
As per the balanced equation, one mole of `CO_(2)` requires 2 moles of ammonia.
`:.` No. of moles of `NH_(3)` REQUIRED to react with 25.95 moles of `CO_(2)` is =
`2/1 xx 25.95` = 51.90 moles.
`:.` 37.45 moles of `NH_(3)` is not ENOUGH to completely react with `CO_(2)` (25.95 moles).
HENCE, `NH_(3)` must be the limiting reagent, and `CO_(2)` is excess reagent.
(b) 2 moles of ammonia produce 1 mole of urea.
`:.` Limiting reagent 37.45 moles of `NH_(3)` can produce `1/2 xx 37.45`moles of urea
= 18.725 moles of urea.
The mass of 18.725 moles of urea = No. of moles `xx` Molar mass
= 18.725 `xx` 60 = 1123.5 g of urea.
(C) 2 moles of ammonia requires 1 mole of `CO_(2)`
`:.` Limiting reagent 37.45 moles of `NH_(3)` will require` 1/2 xx 37.45` moles of `CO_(2)`
= 18.725 moles of `CO_(2)`
`:.` No. of moles of the excess reagent `(CO_(2))` left = 25.95- 18.725 — 7.225
The mass of the excess reagent `(CO_(2))` left = `7.225xx44`
= 317.9 g of `CO_(2)` .
Discussion
2.

Which of the following alcohols would undergo esterification most readily?

Answer»

`CH_(3)OH`
`CH_(3)CH_(2)OH`
`CH_(3)CH_(2)CH_(2)OH`
`CH_(3)UNDERSET(OH)underset(|)(CH)-CH_(3)`

Solution :Order of REACTIVITY TOWARDS esterification is `CH_(3)OH gt 1^(@) gt 2^(@) gt 3^(@)`.
Discussion
3.

Which substance is used in refrigerator instead of CFC ?

Answer»



SOLUTION :HFC-134a (1, 1, 1, 2, Tetraflouroethane ) is used in REFRIGERATOR instead of CFC.
Discussion
4.

Which one of the following ionic species has the greatest proton affinity to form stable compound ?

Answer»

`I^(-)`
`HS^(-)`
`NH_(2)^(-)`
`F^(-)`

Solution :Strongest PROTON affinity will be for the species which is the strongest BASE or whose conjugate acid is the weakest. The conjugate acid out of HI, `H_(2)S,NH_(3)andHF`.
Discussion
5.

Which of the following statement(s) is(are) correct?

Answer»

vander Waals radius of iodine is more than its covalent radius
All isoelectronic ions belong to the same PERIOD of the periodic table
`IE_1` of N is higher than that of O while `IE_2` of O is higher than that of N
The electron gain enthalpy of N is positive while that of P is negative.

Answer :A::C::D
Discussion
6.

When 2-butyne is treated with H_(2)/Lindlar's catalyst, compound X is produced as the major product and when treated with Na/liq. NH_(3) it produces Y as the major product. Which of the following statements is correct ?

Answer»

X will have HIGHER dipole MOMENT and higher BOILING POINT than Y.
Y will have higher dipole moment and higher boiling point then X.
X will have lower dipole moment and lower boiling point than Y.
Y will have higher dipole moment and lower boiling point than X.

Answer :A
Discussion
7.

When H_(2)S gas is passed through aqueous solution of CuCl_(2), HgCl_(2), BiCl_(3) and CoCl_(2) in the presence of excess of dilute HCl, it fails to precipitate

Answer»

`CuS`
`HgS`
`Bi_(2)S_(3)`
`COS`

SOLUTION :The `k_(sp)` of CoS is QUITE high. In acidic medium, `S^(2-)` ion concentration gets suppressed. The concentration of `Co^(2+)` and `S^(2-)` ions REMAIN less than the `k_(sp)` VALUE of the salt. Therefore, CoS is not precipitated.
Discussion
8.

Which of the following is true about an aqeous solution (saturated) of AgCl?

Answer»

Adding `NaCl` loweres the solubility of `AGCL`.
Adding `Na_(2)CO_(3)` has no EFFECT
Adding aquoeus ammonia increases solubility of `AgCl`
Adding `NaBr` doesn't effect the solubility of `AgCl`.

SOLUTION :N//A
Discussion
9.

What is the relation between reactivity of compound, bond strength and bond order between two carbon atoms ?

Answer»

Solution :As the BOND ORDER between C-C INCREASES bond ENTHALPY increases and bond STRENGTH increases. But as the bond order increases, reactivity of compound increases.
Discussion
10.

Two glass bulbs A and B are connected by very small tube having a stop cock. Bulb A has a volume of 100 ml and contained a gas while bulb B is empty and has a volume of 150 ml. On opening the stop cock, the pressure of the gas in bulb A will fall down to :

Answer»

80% 
60% 
0.4
20% 

Solution :
Total moles INITIALLY and finally is constant
`:. 100 xx p^@ + O = 100 xx P + 150 xx P`
`implies P (100 xx P^@)/(250) = 40%` of `P^@.`
Discussion
11.

Those stereoisomers are called configurational isomers if they differ in spatial arrangement of atom or group and are not interconvertible without cleaving a bond. Geometrical isomer arises due to restricted rotation about a bond or centre. The number of G.I is 2^(n) where n= number of stereoisomers, in some cases the number of G.I is less than 2^(n) in case where either side nomenclature will be possible. Which of the following compounds can show geometrical isomerism.

Answer»




SOLUTION :Allenes with EVEN are not planar & not SHOW G.I
Discussion
12.

Which of the bicarbonate does not exist in solid state?

Answer»

`NaHCO_(3)`
`KHCO_(3)`
`Ca(HCO_(3))_(2)`
`RbHCO_(3)`

ANSWER :C
Discussion
13.

While filling electrons in pi_(2p_(x)) and pi_(2p_(y)), the electronic configuration rules that one to be followed is

Answer»

PAULI's exclusion PRINCIPLE
Aufbau principle
Both Pauli's and Hund's rule
All the above

ANSWER :C
Discussion
14.

Which of the following is electron donor?

Answer»

`-COOH`
`-NO_(2)`
`C_(6)H_(5)^(-)`
`(CH_(3))_(3)C-`

ANSWER :D
Discussion
15.

Which of the followinte test will not be given by (Squaric acid)

Answer»

`Br_(2)` water test
2,4-DNP test
NEUTRAL `FeCl_(3)`
TOLLEN's test

SOLUTION :Termianal alkyne and -CH=O group gives positive test with tollens REAGENT.
Discussion
16.

Which one of the following statement is false ?

Answer»

Photochemical SMOG CAUSES IRRITATION in eyes
London smog is a mixture of smoke and fog
Photochemical smog RESULTS in the FORMATION of PAN
London smog is oxidising in nature

Solution :(d) is false as London smog is reducing in nature.
Discussion
17.

Two identical vessels are filled with 44g of Hydrogen and 44g of carbon dioxide at the same temperature. If the pressure of CO_(2)is 2 atm, the pressure of Hydrogen is

Answer»

1 ATM
44 atm
2 atm
22 atm

Answer :D
Discussion
18.

Which of the following statements is not correct from the view point of molecular orbital ?

Answer»

` Be_2` is not a stable molecule
`He_2` is not stable but `He^(+)` is expected to exist
Bond strength of `N_2` is MAXIMUM AMONGEST the homonuclear diatomic molecules
The order of energies of molecular orbitals in `F_2` molecule is `E (sigma 2s) lt E ( sigma^(** ) 2s ) LTE ( pi 2p_x ) `
`=E(poi 2p_y ) ltE ( sigma 2p_z ) lt E ( pi^(**) 2p_x)`
`=E ( pi^(**) 2p_y)lt E ( sigma^(** ) 2p_z)`

Answer :D
Discussion
19.

Which of the following species will be isoelectronic with Ne?

Answer»

`N^(3-)`
`Na^+`
`Al^(3+)`
`F^-`

ANSWER :A::B::C::D
Discussion
20.

Which is the correct relationship between wavelength and momentum of particles

Answer»

`lambda=h/P`
`pi=h/P`
`P=h/(lambdam)`
`h=P/lambda`

Solution :We know that the correct relationship between WAVELENGTH and MOMENTUM is `lambda=h/p` . Which is GIVEN by de-Broglie.
Discussion
21.

Those stereoisomers are called configurational isomers if they differ in spatial arrangement of atom or group and are not interconvertible without cleaving a bond. Geometrical isomer arises due to restricted rotation about a bond or centre. The number of G.I is 2^(n) where n= number of stereoisomers, in some cases the number of G.I is less than 2^(n) in case where either side nomenclature will be possible. Which of the following pairs has correct stability order :

Answer»




SOLUTION :TRANS STABLE than CIS
Discussion
22.

Which of the following statements are correct about this reaction ?

Answer»

The given reaction follows `S_(N)2` MECHANISM.
(II) and (iv) have OPPOSITE configuration.
(ii) and (iv) have same configuration.
The given reaction follows `S_(N)2` mechanism.

Answer :A::B
Discussion
23.

Write periodicity of ionization enthalpy of 1 to 60 elements of periodic table.

Answer»

Solution :Generally IONISATION ENTHALPY means first IONIZATION enthalpy.
The first ionization enthalpies of elements having atomic numbers up to 60 are plotted in figure.

The periodicity of the graph is quite striking.
You will find maxima at the noble gases which have CLOSED electron shells and very stable electron configurations.
On the other HAND, minima occur at the alkali metals and their low ionization enthalpies can be correlated with their high reactivity.
In period we go left to right ionization enthalpy increases.
In group we go top to bottom ionization enthalpy decreases.
Discussion
24.

What is the equilibrium concentrations of each of the substances in the equilibrium when the initial concentration of I Cl was 0.78 M ? 2I Cl(g) hArr I_2(g) + Cl_2(g) , K_c=0.14

Answer»

Solution :Let at EQUILIBRIUM , `[I_2]=[Cl_2]="x mol L"^(-1)`
`{:(,2ICl(g) hArr, I_2(g) +,Cl_2(g)),("Initial conc.",0.78 M, 0,0),("At EQU.", 0.78-2x, x ,x):}`
`K_c=([I_2][Cl_2])/[IC l]^2`
`0.14=(x xx x)/(0.78-2x)^2`
or `x^2=0.14(0.78-2x)^2`
or `x/(0.78-2x)=sqrt0.14=0.374`
or x=0.292-0.748 x
1.748 x = 0.292
`therefore` x=0.167
Thus, at equilibrium ,
`[I_2]` =0.167 M , `[Cl_2]` =0.167 M , [I Cl]=0.78 - 2 x 0.167 = 0.446 M
Discussion
25.

Which of the following ions is more stable? Use resonance to explain your answer

Answer»

Solution :
Out of the FOLLOWING two ions, carbocation (A) is more stable than carbocation (B) is LESS planar and hence does not undergo resonance. Alternativity, since and endocyclic (within the RING) double bond is more stable than an exocyclic (outside the ring) double bond, THEREFORE carbocation (A) is more stable than carbocation (B)
Discussion
26.

When alpha particles are sent through a thin metal foil most of them go straight through the foil because

Answer»

ALPHA particles are much heavier than electrons
Alpha particles are positively charged
Most PART of the atom is EMPTY
Alpha particles move with high velocity

Solution :RUTHER ford `alpha` - ray scattering expt. Discovery
Discussion
27.

Which resonance form in each of the following sets is the major contributor to the real structure? (i) underset((A))(CH_(2)-underset(CH_(3))underset(|)(C)-CH)=CH_(2)harrunderset((B))(overset(+)(CH_(2))-underset(CH_(3))underset(|)(C)=CH)-overset(-)(CH_(2)) harr underset((C))(overset(-)(CH_(2))-underset(CH_(3))underset(|)(C)=CH)-overset(+)CH_(2) (ii) underset((A))(CH_(3)-overset(O)overset(||)(C)-CH)=CH_(2)harrunderset((B))(CH_(3)-overset(O^(-))overset(|)underset(+)(C)-CH)=CH_(2)harr underset((C))(CH_(3)-overset(O^(-))overset(|)(C)=CH)-overset(+)(CH_(2)) (iii) underset((A))(CH_(2)=CH-CH=CH_(2))harrunderset((B))(overset(+)(C)H_(2)-CH=CH)-overset(-)CH_(2)harrunderset((C))(overset(-)(CH_(2))-CH=CH-overset(+)(CH_(2))

Answer»


Answer :FORM A in (i), (ii), (iii) and form C in (IV) is the major contributor because in these STRUCTURES each atom has OCTET and no formal charge is present.
Discussion
28.

which of the following compound cannot give iodoform when react with IO^(-) (hypolodite)

Answer»

`CH_(3)-underset(O)underset(||)(C)-OH`
`Ph-underset(O)underset(||)(C)-CH_(3)`

SOLUTION :`(CH_(3)-underset(O)underset(||)(C)-),(CH_(3)-underset(OH)underset(|)(OH)-)` GROUPS gives positive IODOFORM test.
Discussion
29.

What type of solids are eletrical conductors, Malleable and ductile ?

Answer»

SOLUTION :METALLIC SOLIDS.
Discussion
30.

Which of the following compound changes the salmon-coloured precipitate of zinc nitroprusside into red?

Answer»

`Na_(2)CO_(3)`
`NaHCO_(3)`
Moist-`SO_(2)`
Moist-`CO_(2)`

ANSWER :C
Discussion
31.

Which one of the following is a better reducing agent for the following reduction. RCOOH rarr RCH_(2)OH

Answer»

`SnCl_(2)//HCL`
`NaBH_(4)`/ether
`H_(2)//PD`
`N_(2)H_(4)//C_(2)H_(5)ONa`

ANSWER :A
Discussion
32.

The Van't Hoff factor (i) for a dilute aqueous solution of the strong elecrolyte barium hydroxide is

Answer»

0
1
2
3

Solution :`Ba (OH)_(2)` dissociates of form `Ba ^(2+) and 2OH^(-)` ION
`alpha = ((i -1))/((N-1))`
` i = alpha ( n -1) +1`
`THEREFORE n = i =3 ` (for `Ba (OH)_(2), alpha =1`)
Discussion
33.

What will be value of 40""^(@)C in Fahrenheit scale ?

Answer»

`183""^(@)F`
`104""^(@)F`
`300""^(@)F`
`113""^(@)F`

Answer :A::B::D
Discussion
34.

Write the mechanism for followingreaction underset("Propane")(CH_(3)-CH=CH_(2))+Hbroverset(C_(6)H_(5)CO_(2)O_(2))rarr underset("1-bromopropane")(CH_(3)-CH_(2)- Br)

Answer»

Solution :`CH_(3)-CH = CH_(2)+ HBroverset(C_(2) H_(5)CO_(2)O_(2))(to)UNDERSET("1-bromopropane")(CH_(3)-CH_(2)- Br)`
thereactionproceeds throughfree radicalmechanism
Step 1 TheweakO- Osinglebondlinkageof peroxideundergoeshomolyliceleavagetogenerate FREE RADICAL

Step :2TheradicalsabstractshydrogenfromHBrthusgeneratingbrominefree radical

Step : TheBrominefree radicaladds to the doublebond in the wayso asto formthemorestablealkylfreeradical

Step : 4Addtionof HBrsecondaryfreeradical
Discussion
35.

Which of the following quantities refers to a saturated solution ?

Answer»

Mol solubility
Solubility
Solubility product
All of these

SOLUTION :The MOLAR solubility of a compound is the number of moles that dissolve to give ONE litre of saturated solution. The solubility of a compound is the amount of the compound that dissolves in a SPECIFIC amount of solvent (water) to form a saturated solution. In solubility equilibrium calculations, it is usually EXPRESSED as grams per litre of solution. The solubility product is the product of the molar concentrations of constituent in a saturated solution.
Discussion
36.

The solubility of CaF_2 in water is 1.7xx10^(-3) g/100 mL at 298 K temp. Calculate solubility product of CaF_2.

Answer»

SOLUTION :`4.14xx10^(-11)`
Discussion
37.

The value of (n_2 + n_1) and (n_2^2 - n_1^2) for He^+ ion in atomic spectrum are 4 and 8 respectively . The wavelength of emitted photon when electron jump from n_2to n_1is

Answer»

`(32)/(9) R_H`
`(9)/(32) R_H`
`(9)/(32) R_H)`
`(32)/(9) R_H)`

SOLUTION :`(n_2^2 - n_1^2)/(n_2 + n_1) = 8/4`
`IMPLIES((n_2 - n_1)(n_2 + n_1))/((n_2 + n_1)) = (n_2 + n_1) = 2`
`therefore n_2 = 3 , n_1 = 1 impliesbar(upsilon) = Z^2 R[1/(n_1^2)- 1/(n_2^2)]`
`=(2)^2 R (1/((1)^2) - 1/((3)^2))= (32R)/(9) , LAMBDA =(9)/(32R)`
Discussion
38.

When metals X is treatedwith sodiumhydroixdes , a whiteprecipitate (A) isobtained , which is solublein excess of NaOHto give soublecomplex (B). Compound(A)is soublein diluteHCl to form compound (C ). Thecompound (A)when heatedstronglygives (D), which isused to extractmetal.Identify(X), (A), (B), (C ) and (D).Write suitable equationsto supporttheir identities.

Answer»

Solution :Since metal X reacts with `NaOH`to first GIVE a white ppt. (A) which dissolves in excess of NaOH to give a soluble complex (B), therefore , metal (X) must beAl , ppt (A)must be `Al(OH)_(3)`and complex (B) must be sodium tetrahydroxoaluminate (III).
`{:(underset((X))(2Al) + 3NaOH rarr underset(" Aluminium hydroxide (ppt.) ")(Al(OH)_(3)darr) + 3Na^(+)),(underset((A))(Al(OH)_(3))+NaOHrarr underset("Sod. tetrahydroxoaluminate (III)")underset((B))(NA^(+)[Al(OH)_(4)]^(-))):}`
Since (A), i.e,`Al(OH)_(3)` react with DIL. `HCl` to give compound(C), therefore, (C ) must be `AlCl_(3)`.
`underset((A))(Al(OH)_(3)) + 3HCl rarr underset((C ))(AlCl_(3)) + 3H_(2)O`
Since (A)on heatinggives (D)which is used to extract metal (i.e, electrolysis of `Al_(2)O_(3)` gives Al metal),
therefore , (D) must bealumina `(Al_(2)O_(3))`
`underset((A))(2Al (OH)_(3)) OVERSET(Delta)rarr underset((D)) (Al_(2)O_(3)) + 3H_(2)O`
Discussion
39.

What is hydrogen bond ?

Answer»

SOLUTION :The attractive FORCE which binds hydrogen atom of one MOLECULE with electronegtive atom PRESENT is the same or other molecule is called hydrogen bond.
Discussion
40.

Which of the following pairs are not functional group isomers ?

Answer»

II and III
II and IV
I and IV
I and II

Solution :(a) and (c) do not represent pair of functional ISOMERS
Discussion
41.

What is the [HF] in 0.02 M HF solution ?

Answer»

Solution :`(K_a=3.2xx10^(-4))`
HF is weak ACID, its equilibrium established in aqueous solution is as under.
`{:(,HF_((aq))+H_2O_((l)) hArr , H_3O_((aq))^(+)+, F_((aq))^(-)),("Initiall",0.02M,0,0),("At equilibrium",(0.02- CALPHA),calpha,C alpha):}`
If `alpha`=degree of dissociation there so , decrease in concentration of HF = `c alpha`
In solution [HF] =(0.02-0.02 `alpha`)M
=0.02 (1-`alpha`)
but value of `alpha` is much less , so neglible .
`(1-alpha)=1`
Thus, [HF]=0.02(1)=0.02 M
So, most of weak acid remain as a undissociate molecule in solution and therefore its concentration in solution can be taken of INITIAL concentration C.
Discussion
42.

Why C Cl_(4) is added in bromination of alkene ?

Answer»

Solution :`C Cl_(4)` is liquid solvent, which is non-polar solvent. Bromine is soluble in non-polar liquid. So, on formation of bromine solution it become CAPABLE to REACT with non-polar alkene.
Discussion
43.

When density of ideal gas is maximum ?

Answer»

<P>

SOLUTION :At HIGH pressure and low temperature.
Because `d=(Mp)/(RT), d prop p prop (1)/(T)`
Discussion
44.

What is the ratio of coefficients of caustic soda and zinc metal in the reaction between zinc and NaOH?

Answer»

Solution :The SKELETON equation is
`NaOH+Zn to Na_(2)ZnO_(2)+H_(2)`
The balanced equation is
`2NaOH+Zn to Na_(2)ZnO_(2)+H_(2)`
The RATIO of coefficent of NaOH and Zn=2:1
Discussion
45.

Which occupy peak of the atomic volume curve-

Answer»

TRANSITION element
halogens
alkali metals
alkaline EARTH metals

Answer :C
Discussion
46.

What is dehydrohalogenation ?

Answer»

SOLUTION :REMOVAL of halogen acid (HX) from the ALKYL halide is CALLED dehydrohalogenation.
Discussion
47.

Which of the following does not have an active methylene group ?

Answer»

`CH_(3)CH_(2)NO_(2)`
`CH_(3)COCH_(2)COCH_(3)`
`PhCOCH_(2)CN`
`CH_(3)CH_(2)NH_(2)`

ANSWER :D
Discussion
48.

Which of the following option is incorrect?

Answer»


`H_2 Noverset(a)toNH_2ltH_3overset(o+) Noverset(b ) tooverset(o+) (NH_3) `( bondlength )
`NH_(3) lt NF_(3)` (DIPOLE MOMENT )
`SiCI_(4) lt "CCI"_(4)` (solubility in WATER )

Answer :A::B::C::D
Discussion
49.

Two liters of an ideal gas at a pressure of 10 atm. expands isothermally into a vacuum until its total volume is 10 liters. How much heat is absorbed and how much work is done in the expansion ?

Answer»

<P>

Solution :We have `q=-w= p_(ex) (10-2) = 0(8) =0` no WORK is done, no HEAT is absorbed
Discussion
50.

Which of the following shows iso-structural species ?

Answer»

`NH_(4)^(+)` and `AlCI_(4)^(-) `
`CH_(3)^(-)` and `H_(3)O^(+)`
`SO_(4)^(2-) , PO_(4)^(3)` and `BF_(4)^(-) `
`SiCI_(4)` and `CO_(2)`

Answer :A::B::C
Discussion