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24701.

The rate of a first order reaction is 1.5 xx 10^(-2) mol L^(-1) "min"^(-1) at 0.5 M concentration of the reactant . The half life of the reaction is

Answer»

8.73 min
7.53 min
0.383 min
23.1 min

Solution :Rate `((DX)/(dt))` = k.c, `1.5 xx 10^(-2) = k xx 0.5`
For FIRST order k = `(1.5 xx 10^(-2))/(0.5) = 3 xx 10^(-2) "MINUTE"^(-1)`
`t_(1//2) = (.693)/(k) = (.693)/(3 xx 10^(-2)) = 23.1` minute.
24702.

The rate of a first order reaction is 0.04" mol L"^(-1)s^(-1) at 10 seconds and 0.03" mol L"^(-1)s^(-1) at 20 seconds after initiation of the reaction. The half-life period of the reaction is

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`44.1" s"`
`54.1" s"`
`24.1" s"`
`34.1" s"`

Solution :For a FIRST order reaction. `A to` product, and for concentration of the REACTANT at TWO different TIMES
`k = (2*303)/((2)-t_(1)) log""([A]_(1))/([A]_(2))`
Also for first order reaction, rate `alpha` [A]. Hence
`k=(2*303)/(t_(2)-t_(1))log""(("Rate")_(1))/(("Rate")_(2))`
`=(2*303)/((20-10))log((0*04)/(0*03))=0*0287 s^(-1)`
`t_(1//2)=(0*693)/(k)=(0*693)/(0*0287s^(-1))=24*14s`
24703.

The rate of a first order reaction is 0 04 mol L^-1s^-1 at 10 seconds and 003 molL^-1s^-1at 20 seconds after initiation of the reaction. The half life period of the reaction is

Answer»

24.1 s
34.1 s
44.1 s
54.1 s

Answer :A
24704.

The rate of a first order reaction is 0.69xx10^(-2) min^(-1) and the initial concentration is 0.5mol L^(-1) . The half life period is

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3000 s
0.33 s
50 s
100 s

Solution :(A) Rate = K[C]
`0.69xx10^(-2) = k[0.5]`
or `k = (0.60xx10^(-2))/(0.5)`
`t_(1//2) = (0.693)/(k) = (0.693xx0.5)/(0.693xx10^(2))`
50 min = 3000 sec
24705.

The rate of a first order reaction is 0.04 mol l^(-1) s^(-1) at 10 seconds and 0.03 mol l^(-1) s^(-1) at 20 seconds after initiation of the reaction . The half-life period of the reaction is

Answer»

24.1 s
34.1 s
44.1 s
54.1 s

Solution :`K = (2.303)/((t_(2) - t_(1))) "log" ((a-x_(1)))/((a-x_(2))) K = (2.303)/((20-10)) "log" ((0.04)/(0.03))`
`K = (2.303 XX 0.1249 )/(10) (2.303 xx "log" 2)/(t_(1//2) = (2.303 xx "log" 2)/(10)`
`t_(1//2) = (0.3010 xx 10)/(0.1249) = 24.1` SEC
24706.

The rate of a first-order reaction is 0.04 mol l^(-1) s^(-1) at 10 seconds and 0.03 mol l^(-1)s^(-1) at 20 seconds after initation of the reaction.The half life perriod of the reaction is ……

Answer»

34.1
44.1 s
54.1s
24.1 s

Solution :`K=(2.303)/(10)`log`(0.04)/(0.03)=(2.303xx0.124)/(10)`
`t_((1)/(2))=(2.303xx0.3010xx10)/(2.303xx0.124)=24.27` second
24707.

the rate ofa first- orderreactionis 0.04 molL^(-1) s^(-1)at 10sec and 0.03 mol L^(-1) S^(-1)at 20 sec afterinitiationof thereaction the half-lifeperiod of the reaction is

Answer»

`34.1s`
44.1 s
54.1s
24.1

Solution :Givenorder of reaction =1
Rateof reaction at 10 s=0.04 MOL `L^(-1)S^(-1)`
rateof reactionat 20s=0.03 `mol L^(-1)S^(-1)`
` therefore ` half - lifeperiod `(t_(1//2))=?`
we have the equation forrate- constant 'K' in firstorderreaction .
`K =(2303)/(t) log""(A_(t))/(A_(0))=(2.303)/(105 ) log""(0.04)/(0.03)`
` =(2.303)/(105)xx0.124`
`k=0.028s^(-1)`
weknow that
`t_(1//2)=(0.693)/(k) =(0.693)/(0.028773391S^(-1))`
`=24.14 s=24.1S`
24708.

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

Answer»

Solution :For a FIRST order reaction, `ATO"PRODUCTS, for concentration of the reactant at two different TIMES,"`
`k=(2.303)/(t_(2)-t_(1))log""([A]_(1))/([A]_(2))`
But as rate `=k[A]," therefore, "(("rate")_(1))/((rate)_(2))=([A]_(1))/([A]_(2))`
Hence, `k=(2.303)/(t_(2)-t_(1))log""(("rate")_(1))/(("rate")_(2))=(2.303)/((20-10)min)log""(0.04)/(0.03)=2.88xx10^(-2)min^(-1)`
`:.t_(1//2)=(0.693)/(k)=(0.693)/(2.88xx10^(-2)min^(-1))=24.06" min "=1443.6 s.`
24709.

The rate of a first order reaction has been found to be 2.45xx10^(-6) "mol L"^(-1) s^(-1) at concentration C_(1). The value of C_(1) is (rate constant = 3.5xx10^(-5)) :

Answer»

7.0 MOL `L^(-1)`
0.7 mol `L^(-1)`
0.07 mol `L^(-1)`
2.1 mol `L^(-1)`

Solution :(C ) Rate = K(C )
`2.45 xx10^(-6) = 3.5 xx10^(-5) xxC_(1)`
or `C_(1) = (2.45xx10^(-6))/(35xx10^(-5))= 0.07 "mol L"^(-1)`
or `([A])/([A]_(0))= 1.77`
`([A]_(0))/([A])= (1)/(1.77) = 56 .35 %`
`:. ` Extent of reaction
`= 100 - 56.3 = 43.75 %`
24710.

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

Answer»

24 times
32 times
64 times
10 times

Solution :(B) : `roverset(10^(@)"rise")to2" r "OVERSET("Further "10^(@)" rise")to4" r "overset("Further "10^(@)" rise")to8" r "overset("Further "10^(@)" rise")to16" r "overset("Further "10^(@)" rise")to32" r"`
Alternatively, as rate of reaction is doubled for EVERY `10^(@)` rise in temperature, increase in reaction rate `=2^(5)=32` times.
24711.

The rate of a chemical reaction is increased in presence of a catalyst. This is because

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activation ENERGY of the REACTION is less in the new path 
heat of reaction is decreased 
threshold energy is INCREASED 
activation energy of the new path is more 

ANSWER :A
24712.

The rate of a chemical reaction doulets for every 10^(@)C rise of temperature. If the temperature is raised by 50^(@)C, the rate of the reaction by about,

Answer»

10 times
24 times
32 times
64times

Solution :SINCE for every `10^(@)C` rise in TEMPERATURE increase in REACTION RATE`=2^(5)=3` times
24713.

The rate of a chemical reaction doubles for every 10^(@)C rise in temperature. If the temperature is increased by 60^(@)C the rate of reaction increases by about

Answer»

20 times
32 times
64 times
128 times

Solution :`x=60/10=6,(r_(2))/(r_(1))=MU^(x),r_(2)=r_(1)xx2^(6)=r_(1)xx64`
24714.

The rate of a chemical reaction doubles for every 10^@C rise in temperature. If .the rate is increased by 60^@C, the rate of reaction increases by:

Answer»

29 times
32 times
64 times
128 times

Answer :C
24715.

The rate of a chemical reaction doubles for every 10^@C rise in temperature. If the rate is increased by 60^@C, the rate of reaction increases by:

Answer»

29 times
32 times
64 times
128 times

Answer :C
24716.

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

Answer»

32 times
64 times
10 times
24 times

SOLUTION :(A) INCREASE in reaction rate `=2^(5)` = 32 times
24717.

The rate of a chemical reaction doubles for an increases of 10 K in absolute temperature from 298 K. Calculate E_e.

Answer»

Solution :log `k_2/k_1=E_1/(2.303R)[(T_2-T_1)/(T_1T_2)]`
SUBSTITUTING we GET ,log 2=`(E_axx10)/(2.303xx8.314xx10^(-3)xx298xx308)`
`thereforeE_a=(0.3010xx2.303xx8.314xx10^(-3)xx298xx308)/10=52089KJmol^(-1)`
24718.

The rate of a chemical reaction doubles for an increase of 10K in absolute temperature from 298K. Calculate E_(a).

Answer»

SOLUTION :52.898 KJ.
24719.

The rate of a chemical reaction decreases as the reaction proceeds. This is because

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The reactant concentration remain CONSTANT as the reaction proceeds.
The PRODUCT concentration REMAINS constant as the reaction proceeds.
Concentration of reactant decreases from time to time, as the reaction progresses
Concentration of product decreases from time to time, as the reaction progresses

Answer :C
24720.

The rate of a chemical reaction…..

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INCREASES as the REACTION proceeds.
decreases as the reaction proceeds
may INCREASE or decrease during the reaction.
remains CONSTANT as the reaction proceeds.

Answer :B
24721.

The rate of a certain reaction is given by, rate = k[H^(+)]^(n). The rate increases 100 times when the pH changes from 3 to 1. The order (n) of the reaction is

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2
0
1
1.5

Solution : RATE (r) = `k[H^+]^N`
When pH = 3 , `[H^+]` = `10^(-3)`
and when pH = 1 , `[H^+]`=`10^(-1)`
`THEREFORE (r_1)/(r_2)=(k(10^(-3))^n)/(k(10^(-1))^n) implies (1)/(100) =((10^(-3))/(10^(-1)))^n (therefore r_2=100 r_1)`
`implies (10^(-2))^1=(10^(-2))^n implies n=1`
24722.

The rate of a certain reaction increases by 2.5 times when the temperature is raised from 300K at 310K. If k is the rate constant at 300K then the rate constant at 310 K will be equal to

Answer»

k
2K
2.5k
3k

Solution :RATE of reaction `prop` Rate constant. As rate of reaction increases 2.5 times, the rate constant will BECOME 2.5 times. (ALTERNATIVELY, TEMPERATURE coefficient = 2.5).
24723.

The rate of a certain reaction depends on concentration according to equation -(d[A])/(dt)=(k_(1)[A])/(1+k_(2)[A]) What will be the order of reaction when (i) concentration is very high (ii) very low ?

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Solution :Given, `-(d[A])/(dt)=(k_(1)[A])/(1+k_(2)[A])`
`IMPLIES(-d[A])/(dt)=(k_(1))/((1)/([A])+k_(2))`
`(i)` When `[A]` is very high `(1)/([A])` is very SMAL , and thus negligible
`:.-(d[A])/(dt)=(k_(1))/(k_(2))=` constant
Thus, ORDER of reaction is ZERO.
`(ii)` When `[A]` is very low.
`[A+k_(2)[A]=k.`
`-(d[A])/(dt)=(k_(1)[A])/(k.)=k.[A]`
Thus order of reaction is one.
24724.

The rate of a certain biochemical reaction catalyesd by an enzyme in human body is 10^4 times faster than when it carried out in the laboratory. The activation energy of this reaction :

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Is zero
Is DIFFERENT in TWO cases
Is the same in both the cases
None

Answer :B
24725.

The rate law of the reaction RCl+NaOHtoROH+NaCl is given by Rate =k[RCI]. The rate of this reaction

Answer»

A & B
B & C
C & D
B & D

Answer :B
24726.

The rate law of the reaction H_2 + Br_2to 2HBr is(d[HBr])/(dt) = k [H_2][Br_2]^(1//2)What is the order of the reaction? Is this an elementary reaction?

Answer»

SOLUTION :`3/2, No`
24727.

the rate law of the reaction A to Product is : rate = k[A]. It has been graphically represented. What is the rate constant for the reaction?

Answer»

Solution :From the graph:
Cast I: Rate = `K[A]`
`1 xx 10^(-3) Ms^(-1) = k(0.1 M)`
`k=(1 xx 10^(-3)Ms^(-1))/(0.1M) = 10^(-2)s^(-1)`
24728.

The rate law of the reaction, A+2B toProduct , is given by d["Product"]//dt=K[A]^(2)*[B]. If A is taken in large excess, the order of the reaction will be

Answer»

`0`
`1`
`2`
`3`

ANSWER :B
24729.

The rate law of the reaction, 2A+ B to 2AC is represented as Rate = K [A]^(2) [B]. If A is taken in large excess, the order of the reaction will be,

Answer»

Zero
1
2
3

Answer :B
24730.

The rate law of nitration of benzene using a mixture of nitric acid and sulphuric acid is

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RATE `=k ["BENZENE"] [NO_(2)^(+)] [H^(+)]`
rate `= k [HNO_(3)] [H_(2)SO_(4)]`
rate `= k ["benzene"] [NO_(2)^(+)]`
rate `= k ["benzene"] [H_(2)SO_(4)]`

Solution :Nitration of benzene is a second order reaction (FIRST order with respect to benzene and first order with respect to `NO_(2)^(+)` ) LTBR. `:.` Rate = `k` [Benzene] `[NO_(2)^(+)]`
24731.

The rate law of a chemical reaction : 2NO+O_(2) to 2NO_(2), is given as rate =k[NO]^(2)[O_(2)]. How will the rate of reaction change if the volume of reaction vessel is reduced to 1//4th of its original value ?

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Solution :For, `2NO+O_(2)to2NO_(2)`
Rate `=k[NO]^(2)[O_(2)]`
Let a MOLES of `NO` and `B` moles of `O_(2)` be taken to start a reaction at any time in a vessel of V litre
`r_(1)=k[(a)/(V)]^(2)[(b)/(V)]`…………`(i)`
If VOLUME of vessel is reduced to `V//4`, then for same moles of `NO` and `O_(2)`
`r_(2)=k[(a)/(V//4)]^(2)[(b)/(V//4)]=64k[(a)/(V)]^(2)[(b)/(V)]`................`(ii)`
By Eqs. `(i)` and `(ii)` , `(r_(2))/(r_(1))=64`
`r_(2)` is `64` times of `r_(1)`
24732.

The rate law from a reaction between the substances A and B is given by rate = k[A]^(n)[B]^(m) On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as

Answer»

(m + N)
(n - m)
`2^((n-m))`
`1/(2^((m+n)))`

ANSWER :C
24733.

The rate law of a chemical reaction given below : 2NO(g) + O_(2)(g) to 2NO_(2)(g) is given as rate =k[NO]^(2).[O_(2)]. How will the rate of reaction change if the volume of reaction vessel is reduced to 1/4th of its original value ?

Answer»


ANSWER :64
24734.

The rate law of a reaction is : Rate = k[A]^(2)[B] On doubling the concentration of both A and B the rate x will become :

Answer»

`4x^(2)`
8X
`x^(3)`
9x

Solution :(B) Let rate = `k [A]^(2) [B] =x `
rate `= k [2A]^(2) [2B] = 8 b[A]^(2) [B] =8x `
24735.

The rate law for the reaction RCL + NaOH(aq) rarr ROH + NaCl is given by Rate = k[RCl]. The rate of the reaction will be

Answer»

unaffected by increasing temperature of the reaction
doubled on doubling the concentration of `NaOH`
HALVED on REDUCING the concentration of `NaOH` to one HALF
halved on reducing the concentration of `RCL` to one half

Solution :`R_(1) = k[RCl]^(1)[NaOH]^(0)`
`R_(2) = k[0.5 RCl]^(1)[NaOH]`
`:. R_(2) = 0.5 R_(1)`
24736.

The rate law for the reactionSucrose + Water overset([H^(+)])to Glucose + Fructose is given by :

Answer»

Rate = K [sucrose] [water]
Rate= K [sucrose] `["water"]^0`
Rate = K `["sucrose"]^0` [water]
Rate = K `["sucrose"]^(1//2) ["water"]^(1//2)`

ANSWER :B
24737.

The rate law for the reaction x A + y B to mP + nQis Rate = k[A]^(c) [D]^(d) . What is the total order of the reaction

Answer»

(x+ y)
(m + N)
( C + d)
x/y

Solution :Orderis the sum of the powers to which the concentration TERMS are RAISED in the rate equation.
24738.

The rate law for the single step reaction 2A + B to 2C is given by

Answer»

RATE=K[A].[B]
`Rate=K[A]^2.[B]`
Rate = K[2A].[B]
`Rate=K[A]^2[B]^o`

Answer :B
24739.

The rate law for the reaction involving BrO_(3)^(-) and Br^(-) in acid mediumis : -(d[BrO_(3)^(-)])/(dt)=k[BrO_(3)^(-)][Br^(-)][H^(+)]^(2) Which of the following comments regarding the reaction are ture -

Answer»

rate does not depend on the concentration of acid
rate change with the variation of pH of the solution
doubling `[H^(+)]` makes QUADRUPLES the rate
it is a pseudo FIRST order REACTION

Answer :A::B::C
24740.

The rate law for the reaction RCl + NaOH (aq) to ROH + NaCl is given by , Rate = k_(1)[RCl]. The rate of the reaction will be

Answer»

DOUBLED on doubling the concentration of sodium hydroxide
HALVED on REDUCING the concentration of alkyl halide to one half
Increased on increasing the temperature of the reaction
Unaffected by increasing the temperature of the reaction.

Solution :As RATE k = [RCl] , on decreasing the concentration of RCl to half , the rate will ALSO be halved . Rate will also increase with temperature .
24741.

The rate law for the reaction 2H_(2(g))+2NO_((g)) to N_(2(g))+2H_(2)O_((g)) is given by rate =-=k[H_(2)][NO]^(2) The reaction occurs in the following two steps: (a) H_(2(g))+2NO_((g)) to N_(2)O_((g))_H_(2)O_((g)) N_(2)O_((g))+ H_(2(g)) to N_(2(g))+H_(2)O_((g)) What is the rate of N_(2)O in the mechanism ? What is the molecularity of each of the elementary stpes ?

Answer»

SOLUTION :Rate of `N_(2)O=K[N_(2)O][H_(2)O]`
Molecularity for 1ST STEP is 3
Molecularity for 2nd step is 2.
24742.

Theratelaw for thereaction C_(2)H_(4)Br_(2)+ 3I^(-) to C_(2) H_(4) + 2Br^(-)+ I_(3)^(-) isRate = k[C_(2)H_(4) Br_(2)][I^(-) ]. Therate of the reactionis found to be1.1 xx 10^(-4) M//s whenthe concentrations of C_(2) H_(4) Br_(2)and I^(-) are0.12 Mand 0.18 M respectively. Calculatethe rateconstantof thereaction.

Answer»


SOLUTION :Given :`C_(2) H_(4)Br_(2)+ 3I^(-) to C_(2) H_(4) + 2Br^(-) + I_(3)^(-)`
Byrate LAW,Rateof REACTION `=R = k XX [ C_(2) H_(4) Br_(2) ][I^(-)]`
`R= 1.1xx 10^(-4)Ms^(-1)`
`[C_(2) H_(4)Br_(2) ]=0.12 M , [I^(-) ]= 0.18 M`
Rateconstant = k = ?
`R= k xx [C_(2)H_(4) Br_(2) ] xx [I^(-)]`
`Ms^(-1)`
`:. k= (R)/([C_(2) H_(4) Br_(2) ] xx [I^(-)])= (1.1 xx 10^(-4))/(underset(M)(0.12)xx underset(M)0.18) = 5.1 xx 10^(-3) M^(-1) s^(-1)`
24743.

The rate law for the reaction: Ester +H^(+)overset("Fast")to Acid + alcohol is: -dx/dt = k["Ester"][H^(+)]^(@) What would be the effect on the rate if the concentration of acid is doubled?

Answer»

SOLUTION :RATE of REACTION will REMAIN UNCHANGED.
24744.

The rate law for the reaction : Ester +H^(+)to"Acid"+"Alcohol is ": (dx)/(dt)=k["Ester"][H^(+)]^(0) What would be the effect on the rate if (i) concentration of the ester is doubled ? (ii) concentration of H^(+) is doubled ?

Answer»

SOLUTION :(i) The rate of REACTION will be doubled. (II) No effect on rate.
24745.

The rate law for the decomposition of N_(2)O_(5) is : rate =k[N_(2)O_(5)]. What is the significance of k in this equation ?

Answer»

Solution :K REPRESENTS the RATE constant or specific reaction rate for the reaction and is equal to the rate of reaction when concentration of `N_(2)O_(5)` is `1" mol L"^(-1)`.
24746.

The rate law for the decomposition of N_(2)O_(5) is given as: Rate =k[N_(2)O_(5)]. What is the significance of k in the equation?

Answer»

Solution :k represents the rate constant for the reaction. It becomes equal to the reaction rate when the molar concentration of `N_(2)O_(5)` is 1 MOL `L^(-1)`.
24747.

The rate law for reaction A+B rarr C is Rate =K[A] [B] Given K=6.93xx10^(-4)M^(-1)sec^(-1) Find the time taken(sec) when concentration of [A] changes from 10^(-4) M to 5xx10^(-5) M Given: [B] =1M

Answer»

10
100
1000
10000

Answer :C
24748.

The rare law for a reaction between th substances A and B is given by Rate =k[A]^(m)[B]^(n) On doubling the concentration of A and halving the concentration of B, the ratio of the new rate to the earlier rate of the reaction will be as

Answer»

`(m+n)`
`(n-m)`
`2^((m-n))`
`(1)/(2^((m+n)))`

ANSWER :C
24749.

The rate law for the chemical reaction : 2NO_(2)Clrarr 2NO_(2)+Cl_(2) is :The rate determining step is :

Answer»

`2NO_(2)Cl RARR 2NO_(2)+2CL`
`NO_(2)+Cl_(2) rarr NO_(2)Cl+Cl`
`NO_(2)Cl+Clrarr NO_(2)+Cl_(2)`
`NO_(2)ClrarrNO_(2)+Cl`

ANSWER :D
24750.

The rate law for a reaction of A,B and C has been found to be rate = k[A]^2[B][L]^(3//2) How would the rate of reaction Change when (i) Concentration of [L] is quadrupled (ii) Concentration of both [A] and [B] are doubled (iii) Concentration of [A] is halved (iv) Concentration of [A] isreduced to (1//3)and consideration of [L] is quadrupled .

Answer»

SOLUTION :Rate `=k[A]^2[B][L]^(3//2)........(1) `
(i) when [L]=[4L]
Rate `=k[A]^2[B][4L]^(3//2)`
Rate = 8 `(k[A]^2[B][L]^(3//2))......(2)`
Comparing (1) and (2) , rate is increased by 8 times.
(ii) when [A] = [2A] and [B] = [2B]
Rate = `k[2A]^2[2B][L]^(3//2)`
Rate = `8(k[A]^2[B][L]^(3//2) )............(3)`
Comparing (1) and (3) , rate is increased by 8 times .
(iii) When `[A] = (([A])/(2))`
Rate `k=(([A]]/2)[B][L]^(3//2)`
Rate `=(1/4)(k[A]^2[B][L]^(3//2))...........(4)`
Comparing (1) and (4) , rate is reduced to `1/4` times.
(IV) when [A] `= (([A])/(3))` and [L]=[4L]
Rate `=k[A/3]^2[B][4L]^(3//2)`
Rate `=(8/9)(k[A]^2[L]^(3//2)).........(5)`
comparing (1) and (5) , rate is reduced to 8/9 times .