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.

For a diatomic molecule AB, the electronegativity difference between A and B=0.2028 sqrt triangle where triangle=[Bond energy of AB- Geometric mean of the bond energies of A_2 and B_2]. The electonegativities of fluorine and chlorine are 4.0 and 3.0 respectively and the bond energies are of F-F : 38 kcal mol^-1 and Cl-Cl : 58 kcal mol^-1. The bond energy of Cl-F is:

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71 kcal/mol
61 kcal/mol
48 kcal/mol
75 kcal/mol

Answer :A
2.

For a decomposition reaction the value of rate constant k at two different temperature are given below : k_1 = 2.15xx10^(-8)" L mol"^(-1)s^(-1)" at "650K""k_2=2.39xx10^(-7)"l mol"^(-1)s^(-1)"at "700K Calculate the value of activation energy for this reaction . (R=8.314"JK "^(-1)mol^(-1))

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SOLUTION :Here `k_1=2.15xx10^(-8)"L mol"^(-1)s^(-1)""k_2=2.39xx10^(-7)"L mol"^(-1)s^(-1)`
`T_1=650K, T_2=700 K and ""R=8.314"JK "^(-1)"mol"^(-1)`
Using the formula
`log k_2/k_1 = (E_a)/(2.303R)[(T_2-T_1)/(T_1T_2)]`
`log (2.39xx10^(-7))/(2.15xx10^(-8))=E_a/(2.303xx8.314)[(700-650)/(650xx700)]`
log `1.111xx10 = E_a/(19.147)xx50/(455000)`
`1.0457=E_a/(19.147)XX1/(9100)`
`E_a = 182202.812J " or " 182.203kJ`
3.

For a d-electron, the orbital angular momentum is

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`sqrt6 ħ`
`SQRT2 ħ`
`ħ`
`2ħ`

Solution :`L= sqrt(l(l+1)) ħ, l=0, 1, 2 ,…., ħ= (H)/(2pi), ħ` is called DIRAC h
4.

For a 'd' electron, the orbital angular momentum is:

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`SQRT((6)H`
`sqrt((2)h`
h
2h

Answer :A
5.

For a d-electron the orbital angular momentum is

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h
`sqrt6h/(2pi)`
`sqrt2h`
`sqrt6h`

SOLUTION :For a d-clcctron, l = 2
ORBITAL ANGULAR MOMENTUM = `sqrt(l(l+1))h/(2pi)`
`=sqrt(2(2+1))h/(2pi)=sqrt6h/(2pi)=sqrt6h`
6.

For a cyclic process, which of the following is not true?

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`DeltaH=0`
`DeltaE=0`
`DeltaG=0`
Total `W=0`

Solution :For a CYCLIC process
`DeltaE=0, DeltaH=0` and `DeltaG=0`. As all depend UPON final state and INITIAL state, W doesn.t depend on path FOLLOWED.
7.

For a cyclic process

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W = 0
`DELTAE = 0`
`DELTAH NE 0`
`DeltaE ne 0`

Solution :For a cyclic PROCESS dE=0 and dH=0.
8.

For a crystal, the angle of diffraction (20) is 90^@ and the second order line has a d value of 2.28 A^@. The wavelength (in A^@) of X-rays used for Bragg's diffraction is

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`1.61Å`
`1.14Å`
`2.28Å`
`2.0Å`

ANSWER :A
9.

For a cubic lattice edge length of unit cell is 5A^(0) and density is 2gcc^(-1). Calculate the radius of an atom, if gram atomic weight is 75 g mol^(-1).

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SOLUTION :`2.17 A^(@)`
10.

For a crystal system a=b=c and alpha=beta=gammane90^(@)

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Tetragonal
HEXAGONAL
Rhombohedral
Monoclinic

Solution :Crystal system AXIAL DISTANCES Axial ANGLES
Tetragonal `a=bnec alpha=beta=gamma=90^(@)`
Hexagonal `a=bnec alphanebeta=90^(@),gamma=120^(@)`
Rhombohedral `a=b=c alpha=beta=gammane90^(@)`
Monoclinic `anebnec alpha=gamma=90,betane90^(@)`
11.

For a crystal of sodium chloride, state : The structural arrangement of the sodium chloride crystal.

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SOLUTION :`Cl^(-)` ION have fcc arrangement and `NA^+`IONS occupy all the ocetahedral sites. Each `Na^+` ion is surrounded by 6 `Cl^(-)` ions and each `Cl^(-)` ion is surrounded by 6 `Na^+` ions.
12.

For a crystal of sodium chloride, state : The number of sodium ions and chloride ions present in unit cell of sodium chloride.

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SOLUTION :`4 NA^+ , 4 CL^(-)`
13.

How many sodium ions and chloride ions are present in a unit cell of sodium chloride ?

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SOLUTION :`4 NA^+ , 4 CL^(-)`
14.

For a crystal of diamond, state : The type of lattice in which it crystallizes.

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Solution :GIANT network TYPE with fcc ARRANGEMENT of C atoms
15.

For a crystal of diamond, state : The number of carbon atoms present per unit cell.

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Solution :Number of particles PER UNIT CELL is 4.
16.

For a crystal of diamond, state : The hybridization of the carbon atom.

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SOLUTION :`sp^3` HYBRIDIZATION
17.

For a covalent solid, the units which occupy lattice points are

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Atoms
Ions
Molecules or atoms
Electrons

Answer :A
18.

For a compound to be purified by steam distillation :

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IMPURITIES must be non-volatile
The LIQUID must be completely immis-cible with WATER
The vapour pressure of the liquid must be sufficiently high
All are correct

Answer :D
19.

For a compound solution of a weak electrolyte A_(x)B_(y) of concentration 'C', the degree of dissociation alpha is given as

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`alpha = sqrt(K_(eq)//C(x+y))`
`alpha = sqrt(K_(eq)C//(xy))`
`alpha = (K_(eq)//C^(x+y-1)X^(x)Y^(y))^((1//(x+y)`
`alpha = (K_(eq)//Cxy)`

Solution :`{:(A_(x)B_(y),HARR,xA^(y+),+,yB^(x-),),(C,,0,,0,"(Initially)"),(C(1-alpha),,Cxalpha,,CY alpha,"(At equilibrium)"):}`
Where `alpha` = DEGREE of dissociation.
`:. K_(eq) = (((Cx alpha)^(x)(Cy alpha)^(y))/(C(1-alpha)))` For concentrated solution of WEAK electrolyte, `alpha` is very small. Therefore, `(1-alpha) ~~ 1`.
`:. alpha = ((K_(eq))/(C^(x+y-1).X^(x).y^(y)))^((1)/(x+y))`.
20.

For a complex reaction……

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order of overall reaction is same as molecularity of the slowest STEP.
Order of overall reaction is LESS than the molecularity of the slowest step
order of overall reaction is GREATER than molecularity of the slowest step.
molecularity of the slowest step is NEVER ZERO or non integer.

Solution :Overall order of complex reaction =molecularity of slow step because rate of reaction =rate of slowest step so order of reaction=molecularity of slow step.
(D)The product is form when reactant is there.So molecularity of reaction can.t be zero or fractional
21.

For a complex reaction

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ORDER of overall reaction is same as MOLECULARITY of the SLOWEST step
order of overall reaction is same as molecularity of the slowest step
order of overall reaction is less than the molecularity of the slowest step
molecularity of the slowest step is never ZERO or non-integer.

Answer :A::D
22.

For a complex reaction ………………. .

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ORDER of overall REACTION is same as molecularity of the slowest step
order of overall reaction is LESS than the molecularity of the slowest step
order of overall reaction is GREATER than molecularity of the slowest step
molecularity of the slowest step is NEVER zero or non integer.

Answer :A::D
23.

For a complex reaction :

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ORDER of overall reactionis same as molcularity of the slowest step (PROVIDED slowest step is having no reaction intermediate)
order of overall reaction is LESS than the molecularity of the slowest step.
order of overall reaction is GREATER than molecularity of the slowest step.
molecularity of the slowest step is never zero or non interger.

Answer :A::D
24.

For a complex reaction _________

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Order of OVERALL REACTION is same as molecularity of the slowest STEP.
Order of overall reaction is less than the molecularity of the slowest step.
Order of overall reaction is greater than molecularity of the slowest step.
None of these above.

ANSWER :A
25.

For a chemical reaction Y_2 + 2Z toProduct,rate conctrolling step is Y + 1/2 Z to Q If the concentration of Z is doubled, the rate of reaction will

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remain the same
become four times
become `sqrt2` times
become double.

Solution :`"Rate"_1=k[Y][Z]^(1/2) and "Rate"_2 =k[Y][2Z]^(1/2)`
`:.("Rate"_2)/("Rate"_1)=(k[A][2Z]^(1//2))/(k[Y][Z]^(1//2))=(2)^(1//2)=sqrt2`
26.

For a chemical reaction……can never be a fraction

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Order
Half-life
Molecularity
Rate constant increases EXPONENTIALLY with DECREASING activation ENERGY and INCREASING temperature.

Answer :C
27.

For a chemical reaction Y_(2)+2Zto Product rate controlling step is Y+1//2ZtoQ. If the concenntration of Z is doubled the rate of reactin will

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REMAIN the same
Become FOUR times
Become `1.414` times
Become double

Answer :C
28.

For a chemical reaction variation in rate with conc. Is shown below : (i) What is the order of the reaction ? (ii) What are the units of rate constant k for the reaction ?

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Solution :(i) ACCORDING to graph there is no CHANGE in concentration with rate so this is zero order reaction.
(II) Unit of (zero order reaction) rate CONSTANT is mol `L^(-1) s^(-1)`.
29.

For a chemical reaction, variation in concentration , in [R] vs time (min) plot is shown: i) What is the order of the reaction? ii) What are units of rate constant, k for reaction?

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SOLUTION :i) The REACTION is of first order.
ii) Units of rate constant(k) `=min^(-1)`
III) `t_(1//2)` remains constant since it is independent of `[R]_(0)` i.e., initial CONCENTRATION of reactants.
iv) For the plot (or graph).
30.

For a chemical reaction, variation in concentration [A] vs time (s) plot in given below: i) Predict the order of the reaction. ii) What does the slope of the line and intercept indicate ? iii) What is the unit of rate constant(k)?

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SOLUTION :i) The reaction is of zero ORDER.
ii) The SLOPE of the line indicates rate constant (k) and INTERCEPT represents `[R]_(0)`
iii) Units of k = `molL^(-1)s^(-1)`
31.

For a chemical reaction to take place, what should be the value of DeltaG ?

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SOLUTION :NEGATIVE
32.

For a chemical reaction, Delta C_(p) is negative (Delta C_(p) lt 0). The heat required to increase temperature of reactans of this reaction by a certain amount =q_(1) and heat required to increase temperature of products of the same reaction by same amount =q_(2), Relate q_(1) and q_(2)

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SOLUTION :N//A
33.

For a chemical reaction, DeltaG will always be negative if

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`DeltaH` and `TDELTAS` both are positive
`DeltaH` and `TDeltaS` both are negative
`DeltaH` is negative and `TDeltaS` is positive
`DeltaH` is positive and `TDeltaS` is negative

Solution :Gibbs-Helmholtz EQUATION is as FOLLOWS :
`DeltaG=DeltaH-TDeltaS`
From Gibbs-Helmholtzequation, it is clear that `DeltaG` will ALWAYS be negative, if `DeltaH` is negative and `TDeltaS` is positive.
34.

For a chemical reaction, mA to xB, the rate law is r=k[A]^2. If the concentration of A is doubled, the reaction rate will be

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doubled
quandrupled
increased by 8 times
UNCHARGED

Solution : `:r=K[A]^(2)`
When CONCENTRATION of A is doubled ,
`r=K[2A]^(2)`
`r=4k[A]^(2)`
35.

For a chemical reaction Ato products, the following equation is found to be followed, logK=16.398-2800/T At 27^(@)C the rate contant of the reaction is ______

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`1.16xx10^(5)`
`1.16xx10^(6)`
`1.321xx10^(7)`
`1.16xx10^(7)`

SOLUTION :`logK=16.398-2000/300=(16.398-9.333)=7.06467,K=10^(7)xx1.16`
36.

For a chemical reaction Ato Products, the rate of disappearance of A is given by: (dC_(A))/(dt)=(K_(1)C_(A))/(1+K_(2)C_(A)) at low C_(A), the reaction is of the _________order with rate constant_________(Assume K_(1), K_(2) are lesser than 1)

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`I,K_(1)//K_(2)`
`I,K_(1)`
`II,K_(1)//K_(2)`
`II,K_(1)//K_(1)+K_(2)`

Solution :1st ORDER `Kt,x/(C_(0))=(1-E^(-Kt)),C_(t)=C_(0).e^(-Kt)`
37.

For a chemical reaction Ato products, the following equation is found to be followed, logK=16.398-2800/T Activation energy of the reaction is _____________K.Cal

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128.13
12.767
12813
1.2813

Solution :`(EA)/(2.303RT)=2800/TimpliesEa=2800xx2.303xx1.98=12.76` KCAL
38.

For a chemical reaction Ato products, the following equation is found to be followed, logK=16.398-2800/T Arrhenius factor for the reaction is ______

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`2.5xx10^(16)`
`5xx10^(16)`
`7.5xx10^(-16)`
`4XX10^(-16)`

SOLUTION :`logK=logA-(EA)/(2.303RT),A=` antilot (16)`xx` ANTILOG `(0.398)=10^(15)xx2.5`
39.

For a chemical reaction at 27^(@)C, the activation energy is 600 R. The ratio of the rate constants at 327^(@)C to that of at 27^(@)C will be

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2
40
E
`e^2`

Solution :In`(k_2)/(k_1)=(E_a)/(R) ((1)/(T_1)-(1)/(T_2))`
or, In`(k_2)/(k_1)=(600R)/(R) ((1)/(300)-(1)/(600))`
or, In `(k_2)/(k_1)=(600R)/(R)((2-1)/(600))=1`
or, In`(k_2)/(k_1)`=In e(`therefore` In e=1)
`(k_2)/(k_1)=e`
40.

For a chemical reaction at constant P, Delta H is equal to

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zero
`Delta U`
`q//T`
`Delta U + p Delta V`

ANSWER :D
41.

For a chemical reaction at constant P and V. Delta H is equal to

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`DELTA U`
ZERO
`Delta U + P Delta V`
`p//T`.

Answer :A
42.

For a chemical reaction at 27^(@)C , the activation energy is 600 R . The ratio of the rate constants at 327^(@)C to that of at 27^(@)C will be

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2
40
E
`e^(2)`

Solution :LN `(K_(2))/(K_(1)) = (E_(a))/(R) ((1)/(T_(1)) - (1)/(T_(2)))` or , ln `(K_(2))/(K_(1)) = (600R)/(R) ((1)/(300) - (1)/(600))`
or , ln `(K_(2))/(K_(1)) = (600R)/(R) ((2-1)/(600)) = 1 `
ln `(K_(2))/(K_(1))` = ln e `"" (K_(2))/(K_(1)) = e`
43.

For a chemical reaction ArarrB, it is found that the rate of reaction doubles when the conc, of 'A' is increased four times. The order of reaction is

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0
0.5
1
2

Answer :B
44.

For a chemical reaction aAtoB,log[-(d[A])/(dt)]=log[(d[B])/(dt)]+0.3 then find the approximate ratio and of a and b

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Solution :`aAtobB-(d[A])/(dt)=(_d[B])/(dt)xx(a/b)`
`LOG((dA)/(dt))=log((DB)/(dt))+log(a/b)` So `log (a/b)=0.3=log2,a/b=2`
45.

For a chemical reaction A_2 +2 B toProducts, the rate con trolling step is A=1/2B to C.If the cone. of B is tripled, the rate of reaction will

Answer»

remain the same
BECOME four times
become 1.732 times
become DOUBLE

Solution :The SLOW step of the reaction is :
`A + 1/2B to C, " rate LOW is,"(dx)/(dt)=k[A][B]^(1//2)`
On TRIPLING the concentration of B, the rate will become `(3)^(1//2)= 1.732` times of the original rate.
46.

For a chemical reaction A to B , the rate of the reaction is 2 xx 10^(-3) mol dm^(-3) s^(-1) . When the initial concentration is 0.05 mol dm^(-3) . The rate of the same reaction is 1.6 xx 10^(-2) mol dm^(-3) s^(-1) when the initial concentration is 0.1 mol dm^(-3) . The order of the reaction is

Answer»

0
3
1
2

Solution :Let the rate EQUATION for the REACTION be ,
rate = `k [A]^(n)`
where , k = rate constant , n = order of reaction
[A] = concentration of reactant
given , `"rate"_(1) = 2 xx 10^(-3) "mol" dm^(-3) s^(-1)`
`[A_(0)] = 0.05 ` mol `dm^(-3)`
`"rate"_(2) = 1 . 6 xx 10^(-2)` mol `dm^(-3) s^(-1)`
`(A_(0)) = 0.1` mol `dm^(-3)`
`therefore 2 xx 10^(-3) = k [0.05]^(n) "".... (i)`
`1.6 xx 10^(-2) = k[0.1]^(n) "".... (ii)`
DIVIDE (i) by (ii)
`implies (2 xx 10^-3)/(1.6 xx 10^(-2)) = ([0.05]^(n))/([0.1]^(n)) = ([0.05]^(n))/(2^(n)[0.05]^(n))`
`implies (1)/(2^(n)) = (1)/(8) implies n = 3, "" therefore` Order of reaction = 3 .
47.

For a chemical reaction, A to products, the rate of reaction doubles when the concentration of 'A' is increased by a factor of 4, the order of reaction is-

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2
0.5
4
1

Answer :B
48.

For a chemical reaction A to B, it was found that concentration of B increases by 0.20 mol L^(-1) in half an hour. What is the average rate of the reaction?

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SOLUTION :For the REACTION `A to B`
`Delta[B]=0.20 mol L^(-1), Deltat=0.5 hour.`
`THEREFORE` AVERAGE rate =`(Delta[B])/(Deltat) = (0.20 mol L^(-1))/(0.5 hr)=0.40 mol L^(-1)hr^(-1)`
49.

For a chemical reactionA to B it is found that the rate of reaction doubles , when the concentration of A is increased four times . The order in A for this reaction is

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Two
One
HALF
ZERO

SOLUTION :`r = k[A]^(m)` also 2r = `k[4A]^(m) , (1)/(2) = ((1)/(4))^(m)`
`therefore m = (1)/(2).`
50.

For a chemical reactio , variation in the concentration [R] Vs time (s) plot is given: For this chemical reaction, write/draw: i) What is the order of the reaction? ii) What are the units of the rate constant (k)? iii) Give the relationship between k and t_(1//2) (half life period) iv) What does the slope of the aboveline indicate? v) Draw the plot log [R]_(0)/[R] Vs time (s).

Answer»

Solution :i) The reaction is of FIRST ORDER.
II) Units of RATE constant (k) = `("time")^(-1)` or `s^(-1)`
iii)Rate constant (k) = `(0.693)/(t_(1//2)`
(iv) The slope of the line is equal to`-(k)`
v) for the graph