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 the density of some lake water is 1.2.5 g mL^(-1) and contains 92 g of Na^(+) ions per kg of water, calculate the molality of Na^(+) ions in the lake.

Answer»

Solution :No. of MOLES of `Na^(+)` ion
`= ("mass")/("molar Mass")`
`= (92 G)/(23g "mol"^(-2))`
= 4 mol
MOLARITY of `Na^(+)` ions = `("No. of moles of "Na^(+) ions)/("Mass of WATER in KG ")`
= `(4 " mol ")/(1 kg )`
` = 4 " mol " kg^(-1) = 4 `m.
2.

In a acid catalysed hydrolysis of an organic compound A, the half-life of A changes from 100 min (when carried out in a buffer sollution of pH=3) to 1 min (when carried out in a buffer solution of pH=4). Both the half lives are independent of concentration nof organic compound. If the rate law is represented as R-K[H^(+)]^(a)[A]^(b) then the values of a and b will be :

Answer»

a = 1, b = 1
a = `-1`, b = 2
a = 2, b = 1
a = `-2`, b = 1

Answer :D
3.

In a 7.0 L evacuated chamber, 0.50 mol H_(2) and 0.50 mol I_(2) react at 427°C H_(2)(g) + I_(2) (g)hArr2HI(g). At the given temperature, K_(c) = 49 for the reaction. What is the partial pressure (atm) of HI in the equilibrium mixture ?

Answer»

6.385
12.77
40.768
646.58

Answer :A
4.

If the density of methanol is 0.793kg L^(-1), what is its volume needed for making 2.5 L of its 0.25 M solutoin?

Answer»

SOLUTION :`"Molar mass of methanol "(CH_(3)OH)="32 g MOL"^(-1)="0.032 kg mol"^(-1)`
`{:("Applying",""M_(1)xxV_(1),=,""M_(2)V_(2)),(,"(Given solution)",,"(Solution to be prepared)"),(,24.78xxV_(1)=0.25xx2.5L,,):}`
`"or"V_(1)=0.02522L=25.22mL`
5.

In a 7.0 L evacuated chamber, 0.50 mol H_(2) and 0.50 mol I_(2) react at 427°C H_(2)(g) + I_(2) (g)hArr2HI(g). At the given temperature, K_(c) = 49 for the reaction. How many moles of the iodine remain unreacted at equilibrium ?

Answer»

0.388
0.112
0.25
0.125

Answer :B
6.

If the density of crystalline CsCI is 3.988 g cm^-3 , calculate the volume effectively occupied by a single CsCl ion pair in the crystal ( CsCl = 168.4 )

Answer»

`7.01 * 10^(-23) cm^3`
`6.02 * 10^(-24) cm^3`
`1 cm^3`
`3.5 * 10^(-23) cm^3`

ANSWER :A
7.

In a 7.0 L evacuated chamber, 0.50 mol H_(2) and 0.50 mol I_(2) react at 427°C H_(2)(g) + I_(2) (g)hArr2HI(g). At the given temperature, K_(c) = 49 for the reaction. What is the total pressure (atm) in the chamber

Answer»

83.14
831.4
8.21
None

Answer :C
8.

If the density of a solvent is greater than 1 kg. dm^(-3) then the molarity (M) and molality (m) are related as

Answer»

M GT m
m gt M
m = M
none of these

Solution :md=M where d = DENSITY of solvent
If `d gt 2 kg dm^(-3), M gt m`
9.

In a 500ml capacity vessel CO and Cl_(2). are mixed to from COCl_(2). At equilibrium, it constains 0.2 moles of COCl_(2) and 0.1 mole of each of CO and Cl_(2). the equilibrium constant K_(c) for the reaction CO+CL_(2) hArr COCl_(2) is

Answer»

5
10
15
20

Solution :`CO+Cl_(2) hArrCoCl_(2)`
`[CO]=(0.1)/(0.5),[Cl_(2)]=(0.1)/(0.5),[COCl_(2)]=(0.2)/(0.5)`
`=([COCl_(2)])/([CO][Cl_(2)])=((0.2)/(0.5))/((0.1)/(0.5)XX(0.1)/(0.5))=2/5xx25=10`
10.

If the density of a solution is "3.12 g mL"^(-1), the mass of 1.5 mL solution in significant figures is ……….. .

Answer»

4.7 g
`4680xx10^(-3)g`
`4.680g`
`46.80g`

SOLUTION :`"MASS of solution "="VOLUME "XX"Density "=1.5mLxx3.12gmL^(-1)`
`=4.68g=4.7g"(in CORRECT significant figures)"`
11.

If the densities of nuclei of ""_(1) H^(1) and ""_(92) U^(238) are X and Y respectively ,then correct relation is

Answer»

X = Y
` X lt Y`
Y = 92 X
Y = 238 X

Solution :DENSITY of NUCLEUS of any NUCLIDE is same
12.

If the DeltaG of a cell reaction AgCl+e^(-)toAg+Cl^(-) is -21.20Kj, The standard e.m.f. of the cell is

Answer»

0.229V
0.220V
`-0.220V`
`-0.110V`

SOLUTION :GIVEN: `DeltaG=-21.20kJ=0.22V`
`becauseDeltaG=-nFE`
`E=(21200)/(1xx96500)=0.2196V=0.22V`
13.

If the degree of dissociation of PCl_5at a certain temperature and 1 atm is 0.2,calculate the pressure at which the substance will be half-dissociated at the same temperature.

Answer»

SOLUTION :0.125 ATM
14.

In a 7.0 L evacuated chamber, 0.50 mol H_(2) and 0.50 mol I_(2) react at 427°C H_(2)(g) + I_(2) (g)hArr2HI(g). At the given temperature, K_(c) = 49 for the reaction. What is the value of K_(p) ?

Answer»

7
49
24.5
None

Answer :B
15.

If the degree of association is 70% for the reaction 2A hArr(A)_2 athe van't Hoff factor for the solute 'A' is

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`0.30`
`0.70`
`0.35`
`0.65`

ANSWER :C
16.

In a 50 - mL solution of H_(2)O_(2)an excess of KI and dilute H_(2)SO_(4)were added The I_(2)so liberated required 20 mL of 0.1 N Na_(2)S_(2)O_(3)for complete reaction . Caculate the strength of H_(2)O_(2) in grams per litre .

Answer»

Solution :`2KL +H_(2)SO_(4) +H_(2)O_(2) to K_(2)SO_(4) +2H_(2)O + I_(2)`
`2Na_(2)S_(2)O_(3) +I_(2) to Na_(2)S_(4)O_(6) +2NaI `
m.e of `H_(2)O_(2)`in 5 mL = m.e of `I_(2)` = m.e of `Na_(2)S_(2)O_(3)`
` :. ` m.e of `H_(2)O_(2)` in 50 mL = `0.1 xx20 = 2 ` ...(EQN.1)
` :. ` m.e of `H_(2)O_(2)` in 1000 mL = `2/50 xx1000 = 40`
Equivalents per litre` = 2/50 xx1000 = 40 `
Equivalents per litre ` = 40/1000`..(Eqn . 3)
Grams per litre of `H_(2)O_(2) = 40/1000 xx 17` ...(Eqn .4)
`(" EQ. wt . of "H_(2)O_(2) = 34/2 = 17 )`
17.

If the current is passed into the solution of an electrolyte

Answer»

ANIONS move TOWARDS anode, cations towards cathode
Anions and cations both move towards anode
Anions move towards cathode, cations towards anode
No movement of ions TAKE place

ANSWER :A
18.

In a 3-litre vessel the following equilibrium partial pressures are measured:N_2 = 190 mm, H_2 = 317 mm, NH_3= 1000 mm. Hydrogen is removed from the vessel until the pressure of nitrogen at equilibrium is equal to 250 mm. Calculate the pressure of other substances under the new condition.

Answer»

<P>

SOLUTION :`P_(H_2) = 265.8mm`
19.

In a 3D hexagonal unit cell of identical atoms, the number of atoms that will contribute their 100% volume within the cell would be:

Answer»


SOLUTION :In this UNIT cell each atom is been SHARED by more than one-unit cell. Thus, no atom is CONTRIBUTING its 100% volume to the unit cell.
20.

If the currentis passed into the solution of an electrolyte :

Answer»

Anions move towards ANODE, cations towards cathode
Anoins and cations both move towards anode
Anions move towards cathode, cations towards anode
No movement of ions takes place

Answer :A
21.

In a 1st order reaction, reactant concentration C varies with times t as:

Answer»

`(1)/(C)` increase LINEARLY with t
LOGC DECREASE linearly with t
C decrease with `(1)/(t)`
logC decrease with `(1)/(t)`

SOLUTION :
22.

If the critical temperature of a gas is 500 K, then which of the following is correct for the same gas ?

Answer»




Solution :(A) at critical TEMPERATURE, the gas does not follow BOYLE's LAW
(C ) `T_(B) = 1687.5 K` as `T_(c ) = 500 K = (8a)/(27Rb)`
(D) It would be CONFIRM CORRECT above its inversion temperature `(3375 K)`
23.

In a 1.0 L aqueous solution when the reaction 2Ag^(+)(aq) + Cu(s) rarr Cu^(2+)(aq) + 2Ag(s) reaches equilibrium,[Cu^(2+)] = xM "and" [Ag^(+)] = yM If the volume of solution is doubled by adding water, then at equilibrium :

Answer»

`[Cu^(2+)] = x/2 M, [Ag^(+)] = Y/2 M`
`[Cu^(2+)] gt x/2 M, [Ag^(+)] gt Y/2 M`
`[Cu^(2+)] lt x/2 M, [Ag^(+)] gt Y/2 M`
`[Cu^(2+)] lt x/2 M, [Ag^(+)] lt Y/2 M`

Solution :CONSIDER the EQUATION : `2Ag^(+)(aq) + Cu(s) rarr Cu^(2+)(aq) + 2Ag(s)`
At equilibrium : `[Cu^(2+)] = xM , [Ag^(+)] = YM`
`K_(eq) = K_(c) = [Cu^(2+)]/[Ag^(+)]^(2) = x/y^(2)`
24.

In a 10 litre box 2.5 mole hydroiodic acid is taken. After equilibrium 2HI

Answer»

2.4
0.15
1.5
`7.5 XX 10^(-2)`

ANSWER :D
25.

If the corrdination number of an element in its crystal lattice is 8, then packing is :

Answer»

fcc
hcp
BCC
none of the above

Solution : bcc ARRANGMENT hasa C. N. of 8.
26.

In a 0.2 molal aqueous solution of a weak acid HX the degree of ionization is 0.3. Taking K_(f) for water as 1.85, the freezing point of the solution will be nearest to

Answer»

`-0.360^(@)C`
`0.260^@)C`
`+0.480^(@)C`
`0.480^(@)C`

SOLUTION :`alpha=(i-1)/(n-1)or 0.3=(i-1)/(2-1)`
i=1.3.
`DeltaT_(f)=iK_(f)m`
`=1.3xx(1.85 K KG mol^(-1))xx(0.2 mol kg^(-1))`
=0.480 K.
f.p. of solution = 0-0.480 K.
`=-0.480K=-0480^(@)C`.
27.

If the configuration of manganese is [Ar]3d^(6),4s^(2), then maximum oxidation number of m anganese will be

Answer»

`+7`
 `+6`
`+2`
`+4`

ANSWER :A
28.

In a 0.2 molal aqueous solution of aweal acid, HX, the degree of dissociation is 0.3 . Taking K_(f) for water as 1.85, the freezing point of the solution will be nearest to

Answer»

`-0.360^(@)C`
`-0.206^(@)C`
`+0.480^(@)C`
`-0.480^(@)C`

Solution :The weak ACID ionizes as
`{:(,HX,hArr,H^(+),+,X^(-)),("INITIAL",1,,0,,0),("After dissociation",1-0.3,,0.3,,0.3):}`
TOTAL MOLES `=1-0.3+0.3+0.3=1.3`
`i=(1.3)/(1)=1.3`
`DeltaT_(f)=iK_(f)xxm=1.3xx1.85xx0.2=0.481`
`T_(f)=0-0.481= -0.481^(@)C`.
29.

if the conductance and specific conductance of a solution is one then its cell constant would be

Answer»

1
zero
0.5
4

Solution :`(K)/(C)=`CELL CONSTANT.
30.

If the concentraton of the reactants is increased ,the rate of reaction

Answer»

REMAINS unaffected
increases
decreases
may INCREASE or decrease

Answer :B
31.

If the concentrations of Fe^(2+)and Fe^(3+)are equal, what should be the concentration of Ag^+ions to have zero voltage for a galvanic cell made up of Ag^(+)|Agand Fe^(3+)| Fe^(2+)electrodes. Also, calculate the equilibrium constant at 25^@Cfor the following cell reaction: Fe^(2+) + Ag^+ = Fe^(3+) + Ag.

Answer»

SOLUTION :0.33M, 3.0
32.

If the concentrations are expressed in mole litre^(-1) and time in sec then the units of the rate constant for the first order reaction are :

Answer»

MOL `litre^(-1) sec^(-1)`
`mol^(-1) "litre sec"^(-1)`
`sec^(-1)`
`"mol"^(2) "litre"^(-2) "sec"^(-1)`

Answer :C
33.

In 3d-series,manganese shows maximum number of oxidation states.

Answer»


ANSWER :A
34.

If the concentration units for the first order reaction is increased by 'm' times, then the rate constant k will be

Answer»

km
k + m
k/ m
k

Solution :Rate constant , k , for a first order reaction is ` k = (2.303)/(t) "log" (a)/(a-x)`
On increasing the concentration UNITS by m times ,
`k'= (2.303)/(t) "log" (ma)/(m (a-x))`
or k' = k, thus , the VALUE of first order rate constant REMAINS the same onchanging the concentration units .
35.

In 3d-series which element has positive E_(M^(2+)//M)^(@) value? Why?

Answer»


ANSWER :CU
36.

If the concentration units are reduced by n times, then the value of rate constant of first order will

Answer»

increase by n times
DECREASE by factor of n
not change
none

Solution :Rate CONSTANT is characteristic constant of a reaction and DEPENDS only on TEMPERATURE and CATALYST .
37.

In 3d-series which element cannot displace hydrogen gas from dilute acids? Why?

Answer»


ANSWER :CU
38.

In 3d series which element has highest melting point

Answer»

V
Zm
Cu
Cr

Answer :D
39.

If the concentration units are reduced by n times, then the value of rate constant of first order will:

Answer»

INCREASE by N times
Decrease by FACTOR of n
Not change
None of the above

Answer :C
40.

In 3d series (Sc to Zn), the enthalpy of atomization of Zn is low. Why ?

Answer»

SOLUTION :DUE to ABSENCE of UNPAIRED ELECTRONS.
41.

If the concentration of water vapour in the air is 1% and the total atmospheric pressure equals to 1 atm then the partial pressure of water vapours is

Answer»

100 atm
1MM Hg
7.6 MM Hg
0.1 atm

Answer :C
42.

In 2002 A.D. according to research the concentration of CFC reached to

Answer»

326 ppb
1750 ppb
261 ppm
368 ppm

Answer :C
43.

If the concentration of water vapour in the air is 1% and the total atmospheric pressure equals 1 atm then the partial pressure of water vapour is :

Answer»

0.1 atm
1 MM Hg
7.6 mm Hg
100 atm

Answer :C
44.

If the concentration of OH^(-) ions in the reaction Fe(OH)_(3)(s)hArr Fe^(3+)(aq)+3OH^(-)(aq)is decreased by 1/4 times, then equilibrium concentration of Fe^(3+) will increase by

Answer»

8 times
16 times
64 times
4 times

Solution :`Fe(OH)_(3)(s)hArr Fe^(3+)(AQ)+3OH^(-)(aq)`
`K=[Fe^(3+)][OH^(-)]^(3)`
Concentration of `OH^(-)` ion in the REACTION is decreased by 1/4 times, then equilibrium concentration of `Fe^(3+)` will be increased by `(4)^(3)=-64` times in order to keep the value of K to be CONSTANT.
45.

If the concentration of OH^(-) ions in the reaction Fe(OH)_(3) hArr Fe^(3+)(aq)+3OH^(-)(aq) is decreased by 1/4 times, then equlibrium concentration of Fe^(3+) will increase by

Answer»

64 TIMES
4 times
8 times
16 times

SOLUTION :`K_(c)=[FE^(3+)][OH^(-)]^(3)`
46.

In 2-butene, which one of the following statements is true ?

Answer»

`C_1 - C_2` BOND is a `sp^3 - sp^3 SIGMA`- bond
`C_2-C_3" bond is a " sp^3 - sp^2 sigma`- bond
`C_1 - C_2" bond is a " sp^3 - sp^2 sigma`-bond
`C_1 - C_2 " bond is a " sp^2 - sp^2 sigma `- bond

Answer :C
47.

If the concentration of lead iodide in its saturated solution at25^@C be 2xx10^(-3) mol per litre its solubility product is :

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`4XX10^(-6)`
`8XX10^(-12)`
`6xx10^(-12)`
`32xx10^(-9)`

ANSWER :D
48.

In 1st row transition series the highest oxidation number is shown by

Answer»

Fe
Mn
Cr
Ti

Answer :B
49.

If the concentration of N_2 ,H_2 and NH_3 are 1,2,3, respectively , their concentration at equilibrium will be : N_2 + 3H_2 hArr 2NH_3.

Answer»

(1-x) (2-3x) (2X)
(1-x/3) (2-x) (2x/3)
(1-x) (2-x) (3+x)
(1-x) (2-3x) (3+2x)

ANSWER :D
50.

In 1984, the Bhopal gas tragedy took place because methyl isocyanate :

Answer»

REACTED with ammonia
Reacted with water
Reacted with DDT
Reacted with CO

Answer :B