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24651.

The rate of chemical reaction depends on the nature of chemical reactions, because:

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The threshold ENERGY level DIFFERS from one reaction to another
Some of the reactant are solid at room temperature
Some of the REACTANTS are coloured
All

Answer :A
24652.

The rate of change in concentration of C in the reaction 2A+B to 2C +3D was 1.0 molL^(-1)S^(-1). Calculate the reaction rate as well as rate of change of concentration of A,B, and D

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Solution :We have,
`-(1)/(2)(d[A])/(dt)=(-d[B])/(dt)=(1)/(2)(d[C ])/(dt)=(1)/(3)(d[D])/(dt)=` rate of reaction
`:. (d[C ])/(dt)=1.0 mol L^(-1)sec^(-1)`
`:.-(d[A])/(dt)=(d[C])/(dt)=1.0molL^(-1)sec^(-1)`
`-(d[B])/(dt)=(1)/(2)(d[C])/(dt)=(1)/(2)=0.5molL^(-1)sec^(-1)`
`(d[D])/(dt)=(3)/(2)(d[C])/(dt)=(3)/(2)xx1=1.5mol L^(-1)sec^(-1)`
Rate `=(1)/(2)(d[C])/(dt)=(1)/(2)xx1=0.5molL^(-1)sec^(-1)`
24653.

The rate of change of concentration of (A) for reaction A to B is given by -(d[A])/(dt)=k[A]^(1//3) Derive expression for half-life period of the reaction.

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Solution :`-(d[A])/(dt)=K[A]^(1//3):.-int(d[A])/([A]^(1//3))=k" dt or "-int[A]^(-1//3)d[A]=k" dt "-(3)/(2)[A]^(2//3)=KT+C[int X^(n)dx=(x^(n+1))/(n+1)]""...(i)`
At `t=0,[A]=[A_(0)]:. -(3)/(2)[A_(0)]^(2//3)=C`
Substituting the value of C in eqn. (i),
`-(3)/(2)[A]^(2//3)=kt-(3)/(2)[A_(0)]^(2//3)" or "kt=(3)/(2)[A_(0)]^(2//3)-(3)/(2)[A]^(2//3)=(3)/(2){[A_(0)]^(2//3)-[A]^(2//3)}`
At `t=t_(1//2),[A]=([A_(0)])/(2)`
`:.kt_(1//2)=(3)/(2){[A_(0)]^(2//3)-[(A_(0))/(2)]^(2//3)}`
or `t_(1//2)=(3)/(2k)[A_(0)]^(2//3)[1-(1)/((2)^(2//3))]=(3[A_(0)]^(2//3))/(2k)[((2)^(2//3)-1)/((2)^(2//3))]=(3[A_(0)]^(2//3))/(k)[((2)^(2//3)-1)/(2^(5//3))]`
24654.

The rate of chemical reaction at constant temperature is proportional to

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The amount of products formed
The product of MASSES of the REACTANTS
The product of the molar concentration of the reactants
The MEAN free path of the reaction

Solution :The rate of CHEMICAL reaction `prop` The product of the molar CONC., of the reactants (at constant T).
24655.

The rate of a reaction that not involve gases is not dependent on

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Pressure
TEMPERATURE
CONCENTRATION
Catalyst

SOLUTION :The rate of reaction depends upon conc., of REACTANT , surface area of reactant , temperature , presence of light and catalyst .
24656.

The rate of a reaction that not involve gases is not dependent on:

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PRESSURE
TEMPERATURE
CONCENTRATION
CATALYST

ANSWER :A
24657.

The rate of a reaction qudruples when the temperature changes from 293 K to 313 K.Calculation the energy of activation of the reaction assuming that it does not change with temperature.

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SOLUTION :`T-(1)`=293 K
rate=`r_(1)`
means `k_(1)` and
`E_(a)`=(?)
`T_(2)`=313K
rate =`r_(2)=4r_(1)`
`k_(2)=4k_(1)`
log `(K_(2))/(k_(1))`=log `(4k_(1))/(k_(1))` =log 4
log `(k_(2))/(k_(1))=(E_(a))/(2.303xx8.314)((313-293)/(313xx293))`
`therefore 0.6021=(E_(a))/(2.303xx8.314)((20)/(313xx293))`
`therefore E_(a)=(0.6021xx2.303xx8.314xx313xx293)/(20)`
24658.

The rate of a reaction quadruples when the tamperature changes from 300 to 310k. The activation energy of this reaction is : (Assume activation energy and pre-exponential factor are independent of temperature , In2=0.693, R=8.314J*mol^(-1)*K^(-1))

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`107.2kJ*mol^(-1)`
`53.6kJ*mol^(-1)`
`26.8kJ*mol^(-1)`
`214.4kJ*mol^(-1)`

SOLUTION :`In(k_(1))/(k_(2))=(E_(a))/(R)[(1)/(T_(1))-(1)/(T_(2))]`
`IN4=(E_(a))/(8,314)((310-300)/(310times300))`
`2In2=(E_(a))/(8,314)((310-300)/(310times300))`
`E_(a)=107.2kJ*mol^(-1)`
24659.

The rate of a reaction quadruples when the temperature changes from 293 K to 313 K. Calculate the energy of activation of the reaction, assuming that it does not change with temperature.

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SOLUTION :Using the relation
`"log"(k_(2))/(k_(1))=(E_(a))/(2.303R)[(T_(2)-T_(1))/(T_(1)T_(2))]`.
In this CASE, `k_(2)=4k_(1)`
`therefore "log"(4k_(1))/(k_(1))=(E_(a))/(2.303R)[(T_(2)-T_(1))/(T_(1)T_(2))]`
Substituting the VALUES, we get
`log 4=(E_(a))/(2.303x8.314)[(313-293)/(293xx313)] or 0.6021=(E_(a))/(19.147) xx (20)/(91709)`
or `E_(a)=(0.6021xx19.147xx91709)/(20) or E_(a)=52862"J mol"^(-1)=52.862"kJ mol"^(-1)`.
24660.

The rate of a reaction may be expressed by the following different ways : (1)/(2) (d[X])/(dt)=-(1)/(3) (d[Y])/(dt)=-(d[Z])/(dt) The reaction is :

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`3 Y +Z rarr2X `
`2X+Yrarr Z`
`3X+2Yrarr 6Z`
`2Y +6Z rarr3X`

ANSWER :A
24661.

The rate of a reaction is expressed in different ways as follows +(1)/(2)(d[C])/(dt)=-(1)/(5)(d[D])/(dt)=+(1)/(3)(d[A])/(dt)=-(d[B])/(dt) The reaction is

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`4A+B to 2C+3D`
`B+5D to 3A+2C`
`4A+2B to 2C`
`B+(1)/(2)D to 4A+2C`

ANSWER :B
24662.

The rateof a reactionis givenas , rate= k[X]^(3//2) [Y]^(-1//2) Whatis the orderof thereaction ? If Y is takenlarge in excess , writethe rate equation.

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Solution :Rate LAW of the reaction is given as, rate `=k[X]^(3//2)[Y]^(-1//2)`.
ORDER with respect to X is 3/2
Order with respect to Y is -1/2
Over all order of the reaction `=3//2-1//2=1`
If Y is taken large in excess, the rate is INDEPENDENT of its concentration, as [Y] is taken as constant during the course of reaction.
The rate EQUATION where X is isolated is rate `=k[X]^(3//2)`.
24663.

The rate of a reaction is expressed in the units

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L `"mol"^(-1)t^(-1)`
mol `DM^(-3)t_(-1)`
Ms
`M^(-1)s^(-1)`

Answer :A::B::C::D
24664.

The rate of a reaction is doubled when the concentration of reactant is doubled. What is the order of the reaction ?

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two
one
half
one and a half

SOLUTION :For a FIRST order REACTION,
rate `PROP` CONC. Of rectant.
24665.

The rate of a reaction is doubled for every 10^(@)C rise in temperature . The increase in reaction rate as a result of temperature rise from 10^(@) C to 100^(@)C is

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112
512
400
614

Solution :`(k_(t) + 10)/(k_(t)) = (r_(t) + 10)/(r_(t)) = 2`.
For an increase to `90^(@)C` i.e. 9 times , the rate increases by `2^(9)` times i.e. 512.
24666.

The rate of a reaction is doubled for every 10^@C rise in temperature. The increase in rate as a result of increase in temperature from 10^@C to 100^@C is:

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112
512
400
256

Answer :B
24667.

The rate of a reaction ((dx)/(dt)) varies with nature, physical state and concentration of reactants, temperature, exposure to light and catalyst, whereas rate constant (K) varies with temperature and catalyst only. The rate constant K is given as K=Ae^(pmE_(a)//RT)where A is Arrhenius parameter or pre-exponential factor and E_(a) is energy of activation. The minimum energy required for a reaction is called threshold energy and the additional energy required by reactant molecules to attain threshold energy level is called energy of activation. At what conditions exponential factor is 1 for a reaction:

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Infinite temperature
FREE RADICAL combination
`E_(a) =0`
All of these

Answer :D
24668.

The rate of a reaction gets doubled when the temperature change from 7^(@)C to 17^(@)C. By what factor will it change for the the temperature change from 17^(@)C to 27^(@)C ?

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`1.81`
`1.71`
`1.91`
`1.76`

ANSWER :C
24669.

The rate of a reaction increases to four times when the prevailing temperature is raised from 300 K to 320 K. Calculate the energy of activation of this reaction assuming that it does not change with temperature.""[R=8.314"J mol"^(-1)K^(-1)]

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Solution :Arrhenius EQUATION relating the RATE CONSTANT and temperature is given below:
`"log"(k_(2))/(k_(1))=(E_(a))/(2.303R) xx ((1)/(T_(1)) - (1)/(T_(2)))`
SUBSTITUTING the values, we get
`log 4= (E_(a))/(2.303xx8.314)xx ((1)/(300)-(1)/(320)) or log 4= (E_(a))/(19.147) ((20)/(300xx320))`
`or E_(a)=(19.147 xx 32xx3xx0.6021)/(20)=55.336"kJ mol"^(-1)`.
24670.

The rate of a reaction doubles when its temperature changes from 300 K to 310 K.Activation energy of such a reaction will be: (R=8.314 JK^(-1)mol^(-1) and log 2=0.301)

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53.6 KJ `MOL^(-1)`
48.6 KJ `mol^(-1)`
58.5 KJ `mol^(-1)`
60.5 KJ `mol^(-1)`

ANSWER :A
24671.

The rate of a reaction increased from 2 units to 54 units due to change in temperature from 27^(@)C to 57^(@)C. What is the approximate temperature coefficient of the reaction.

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SOLUTION :`(r_(2))/(r_(1))=mu^(x),(54X)/(2R)=mu^(3),27=mu^(3),3^(3),mu=3`
24672.

The rate of a reaction doubles when its temperature changes from 300 K to 310 K . Activation energy of such a reaction will be : (R = 8.314 JK^(-1) mol^(-1) and log2 = 0.301)

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`53.6 kJ mol^(-1)`
48.6 kJ `mol^(-1)`
58.5 kJ `mol^(-1)`
60.5 kJ `mol^(-1)`

SOLUTION :log `(K_(2))/(K_(1)) = (-E_(a))/(2.030R) ((1)/(T_(2)) - (1)/(T_(1)))`
`(K_(2))/(K_(1)) = 2 , T_(2) = 310 K"" T_(1) = 300` K
`implies ` log `2 = (-E_(a))/(2.303 XX 8.314 ) ((1)/(310) - (1)/(300))`
`implies E_(a) = 53598.6` J/mol = 53.6 KJ/mol
24673.

The rate of a reaction depends upon the temperature and is quantitatively expressed as K=Ae^(-E_(a)//RT) (i) If a graph between log K and 1/t write the expression for the slope of the reaction ? (ii) If at under different condition E_(a1)and E_(a2) are the activation energy of two reactions . If E_(a1)=40j/mol and E_(a_(2))=80j/mol. Which of the two has larger value of the rate constasnt ?

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Solution : In `k=-(E_(a))/(RT) + In A`
This equation is of the tyep y = MX+ C
SLOPE` = -(E_(a))/( R)`
(ii) Smaller the ACTIVATION a=energy activation energy , GREATER is the value of rate cosntant .
`therefor E _(1)> K_(2)`
24674.

The rate of a reaction doubles when its temperature changes from 300 K to 310 K. Activation energy of such a reaction will be

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`60.5" KJ MOL"^(-1)`
`53.6" kJ mol"^(-1)`
`48.6" kJ mol"^(-1)`
`58.5" kJ mol"^(-1)`

ANSWER :B
24675.

The rate of a reaction doubles for energy 10^(@)C rise of temperature. If the temperature is raised by 50^(@)C, the rate of reaction increases by about

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10 TIMES
24 times
32 times
64 times

Answer :C
24676.

The rate of a reaction depends upon the

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Volume
pressure
force
concentration of reactant

Answer :D
24677.

The rate of a reaction depends upon

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CONCENTRATION of reactant
temperature
catalyst
all of these

Answer :D
24678.

The rate of a reaction depends on all factors except :

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reaction temperature
concentration of reactants
magnitude of EQUILIBRIUM CONSTANT
specific rate constant.

Solution :(C ) Rate of a reaction does not DEPEND upon the magnitude of equilibrium constant .
24679.

The rate of a reaction can be increased in general by all the factors except:

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USING a catalyst
Increasing the temperature
Increasing the ACTIVATION energy
Increasing the CONCENTRATION of reactants

Answer :C
24680.

The rate of a reaction can be increased in general by all the factors except

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USING a catalyst
increasing the TEMPERATURE
invreasing the ACTIVATION energy
increasing the conc. of REACTANTS

Solution :Energy of activation increase, RATE of reaction will decrease.
24681.

The rate of a reaction becomes four times when the temperature changes from 293 K to 313 K. Calculate the energy of activation (E_(a)) of the reaction aassuming that it does not change with temperature.

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Solution :Given if rate at 293 K is R thus at 313 K rate BECOMES = 4R
`LOG.(k_(2))/(k_(1)) = (E_(a))/(2.303 R)[(T_(2)-T_(1))/(T_(1) xx T_(2))]`
`log.(4R)/(R ) = (E_(a))/(2.303 xx 8.314)[(313 - 298)/(293xx 313)]`
`log4 = (E_(a))/(19.1471)[(20)/(91709)]`
`0.6021 = (E_(a))/(19.1471)[(20)/(91709)]`
`(0.6021 xx 19.1471 xx 91709)/(20) = E_(a)`
`E_(a) = 52863.2177 J mol^(-1)`
or `= 52.863 kJ mol^(-1)`
24682.

The rate of a reaction becomes four times when the temperature changes from 293 K to 313 K. Calculate the energy of activation (E_(a)) of the reaction assuming that it does not change with temperature.""[R=8.314JK^(-1)"mol"^(-1), log 4=0.6021]

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Solution :`"log"(k_(2))/(k_(1))=(E_(a))/(2.303R)[(T_(2)-T_(1))/(T_(1)T_(2))]`
Substituting the values, we have
`log 4=(E_(a))/(2.303xx8.314JK^(-1)"mol"^(-1))[(313K-293K)/(293K XX 313K)]`
or `0.6021=(E_(a))/(19.147JK^(-1)"mol"^(-1))xx(20)/(91709K)`
or `E_(a)=(0.6021xx19.147xx91709)/(20)"J mol"^(-1)=52863"J mol"^(-1)=52.86"kJ mol"^(-1)`
24683.

The rate of a reaction at a particular temperature is r and at another temperatureis 2r. What could be approximate difference betweenthe two temperatures?

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SOLUTION :`10^(@)`
24684.

Therate of areactionat 600 Kis 7.5 xx 10^(5)timesthe rate ofthe samereactionat 400 K. Calculatethe energyof activationfor the reaction.

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SOLUTION :Given : `(R_(2))/(R_(1)) = 7.5 xx 10^(5)`
Fromthe hint `,(R_(2))/(R_(1))= (K_(2))/(K_(1)) = 7.5 xx 10^(5)`
Initialtemperature= `T_(1)= 400 K` Finaltemperature = `T_(2) = 600 K`
ENERGYOF activation`=E_(a) = ?`
`log_(10).(k_(2))/(k_(1))= (E_(a) (T_(2)-T_(1)))/(2.303 R xx T_(1) xx T_(2))`
`= (2.303 xx 8.314 xx 400 xx 600)/((600 -400)) log_(10)7.5 xx 10^(5)`
`=(2.303 xx 8.314 xx 400 xx 600xx 5.875)/(200)`
`= 135000 J mol ^(-1)=135 kJ mol^(-1)`
24685.

The rate of a reaction 2X + Y toProducts is given by (d[Y])/(dt) = k[X]^2[Y] if X is present in large excess, the order of the reaction is

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zero
two
ONE
three

Solution :The RATE does not depend UPON the reactant present in excess `THEREFORE` Rate = k [ Y]
Hence , order of REACTION = 1.
24686.

The rate of a reaction Ararr product, increases by a factor of 100, when cone, of ‘A’ is increased 10 fold. The order of the reaction is

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3
2
1
0.5

Answer :B
24687.

The rate of a particular reaction quadruples when the temperature changes from 293 K to 313 K. Calculate activation energy in KJ/mol.

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Solution :`K_2//K_1`=4
`T_1`=293 K , `T_2`=313 K
`logK_2/K_1=-(E_a)/(2.303R)[1/T_1-1/T_2]`
Thus, on calculating and substituting values, we GET :
`E_a=52.86 KJ "MOL"^(-1)`
24688.

The rate of a particular reaction quadruples when the temperature changes from 293K to 313 K. Calculate the energy of activation for such a reaction assuming that it does not change with temperature.

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SOLUTION :`k_(2)=4k_(1)" or "k_(2)//k_(1)=4.`
24689.

The rate of a particular reaction doubles when temperaturechanges from 27^(@) C to 37^(@)C. Calculate the energy of activation of such a reaction.

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Solution :Here, we are given that
When `T_(1)=27^(@)C=300" K, "k_(1)=k("say"). "When "T_(2)=37^(@)C=310" K",k_(2)=2k`
Substituting these VALUES in the equation :
`log""(k_(2))/(k_(1))=(E_(a))/(2.303R)((T_(2)-T_(1))/(T_(1)T_(2))),`
we get, `log""(2k)/(k)=(E_(a))/(2.303xx8.314)XX(10)/(300xx310("J MOL"^(-1)))" or "log2=(E_(a))/(2.303xx8.314)xx(10)/(300xx310("J mol"^(-1)))`
This on solving gives `E_(a)=53598.6" J mol"^(-1)=53.6" kJ mol"^(-1)`
24690.

The rate of a heterogeneous reaction such as iron (solid) and any gas (oxygen) does not depend on

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CONCENTRATION of reactants
surface AREA of reactants
pressure of reactant gases
potential energy of reactant

Solution :RATE not DEPENDS on P.E. of reactant
24691.

The rate of a gaseous reaction is given by the is expression k[A][B].If the volume of the reaction vessel is suddenly reduced to 1//4 of the initial volume, the reaction rate relating to original rate will be

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`1//10`
`1//8`
8
16

Solution :SINCE active mass = CONCENTRATION in moles/litre Thus when the volume of the reaction vessel reduces to `1/4^(th)` of its initial volume the molar concentration of each REACTANT increases four times. Thus
r=K[4A][4B]-16 k [A][B] i.e. 16 times.
24692.

The rate of a gaseous reaction is given by the expression K[A][B]. If the volume of the reaction vessel is suddenly reduced to 1/4 th of the initial volume, the reaction rate relating to original rate will be

Answer»

`1//10`
`1//8`
8
16

Solution :When volume is REDUCED to `(1)/(4)` , CONCENTRATION become FOUR times and reaction RATE become 16 times because it is 2 order reaction .
24693.

The rate of a gaseous reaction is given by k[A] [B]. If the volume occupied by the reacting gases is suddenly reduced to half the original volume, the rate of the reaction relation relative to the initial rate will be

Answer»

`1//8`
`1//4`
`8//1`
4

Solution :Given `r_(1) = K [A]^(x) [B]^(y) … (i)`
On reducing the ORIGINAL volume to HALF , the concentration of reactants A and B will be doubled .
LET the new rate be `r_(2)` . Then , `r_(2) =k [2]^(x) [ 2 B] ^(y) or r_(2) = k xx 4 [A]^(x) [B]^(y) ""... (ii)`
or `r_(2) = 4 r_(1)`The rate will become four times relative to the initial rate .
24694.

The rate of a gaseous reaction is halved when the volume of the vessel is doubled. What is the order of reaction ?

Answer»

SOLUTION :Suppose, order of reaction is n and the reaction is A (G) `to`Products
RATE=`k[A]^n`…(i)
When volume is doubled, molar conc. becomes half and rate of reaction gets halved.
`"Rate"/2=k(A/2)^n`…(ii)
DIVIDING equation (i) by equation (ii),
`(2)^1 =(2)^n`
n=1
24695.

The rate of a gaseous reaction A + Bto C + D is equal to k [A][B]. The volume of the reaction vessel containing these gases is suddenly reduced to one-fourth of the initial volume . The rate of reaction would be

Answer»

`1//16`
`16//1`
`1//8`
`8//1`

Solution :INITIALLY, `"rate"_1 = k[A]^x[B]^y`
When VOLUME of the vessel is REDUCED to one-fourth, concentrations become 4 times. Hence, NEW rate i.e.
`"rate"_2= k[4A]^x[4B]^y`
`:."rate"_2= 16 xx "rate"_1`
24696.

The rate of a first order reaction : R rarr P is 7.5xx10^(-4) molL^(-1) "s"^(-1) . The rate concentration of R is 0.5 mol L^(-1) . The rate constant is :

Answer»

`2.5xx10^(-5) s^(-1)`
`1.5xx10^(-3)s^(-1)`
`4.16xx10^(-7) s^(-1)`
`1.50xx10^(5)s^(-1)`

Solution :(A) Rate `=7.5xx10^(-4) "mol L"^(-1) "MIN"^(-1)`
`(7.5xx10^(-4))/(60) mol L^(-1) s^(-1)`
Rate = k[R]
k = `("Rate")/([R])`
`= (7.4xx10^(-4))/(60xx0.5)`
`= 2.5 xx10^(-5)`
24697.

The rate of a first-order reaction is 1.5xx10^(-2)"mol"L^(-1) at 0.5 M concentration of the reactant. The half-life of the reaction is

Answer»

0.383 min
23.1 min
8.73 min
7.53 min

Answer :B
24698.

The rate of a first order reaction is 1.8xx10^(-3) "mol L"^(-1) when the initial concentration is 0.3 mol L^(-1) . The rate constant in the units of second is :

Answer»

`1xx10^(-2) s^(-1)`
`1xx10^(-4) s^(-1)`
`6xx10^(-2) s^(-1)`
`6xx10^(2) s^(-1)`

Solution :[B] RATE = K( C)
`1.8 xx10^(-3) = k(0.3)`
or `k=(1.8xx10^(-3))/(0.3)`
`= 6xx10^(-3) min^(-1)`
`=(6xx10^(-3))/(60)=1xx10^(-4)s^(-1)`
24699.

The rate of a first order reaction is 1.5xx10^(-2) mol L^(-1) "min"^(-1) at 0.5 M concentration of the reactant . The half life of the reaction is :

Answer»

`23.1 min`
`8.73 ` min
`7.53 ` min
`0.383 `min

SOLUTION :( B) RATE =K [C]
`k= ("Rate")/([C])`
`=(1.5xx10^(-2))/(0.5) `
`3xx10^(-2)`
`t_(1//2)= (0.693)/(3xx10^(-2))`
= 23.1 min
24700.

The rate of a first order reaction is 0.04mol L^(-1) sec^(-1) at 10 minute and 0.03mol L^(-1) at 20 minute after initiation. Find the half life of the reaction.

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Solution :RATE `=K[A]`
`0.04=k[A]_(10)` and `0.03=k[A]_(20)`
`([A]_(10))/([A]_(20))=(0.04)/(0.03)=(4)/(3)`
`t=(2.303)/(k)log.([A]_(10))/([A]_(20))` when `t=10^(1)`min.
`10=(2.303)/(k)log.(4)/(3)`
`k=(2.303)/(10)log.(4)/(3)=0.0288min^(-1)`
`t_((1)/(2))=(0.693)/(k)=(0.693)/(0.0288)=24.06min`.