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24801.

The rate constant of the reaction A to B is 0.6 x 10^-3 Molar per second. If the concentration of A is 5 M then concentration of B after 20 minutes is

Answer»

1.08 M
3.60 M
0.36 M
0.72 M

Solution :It is zero order reaction `THEREFORE 6 XX 10^(-4) = ("con")/(20 xx 60)`
`therefore` Conc., of B = 0.72 M
24802.

The rate constant of the reaction A to B is 0.6xx10^(-3) mole per second. If the concentration of A is 5 M, then concentration of B after 20 minutes is :

Answer»

`0.36` M
`0.72` M
`1.08` M
`3.60` M

Answer :B
24803.

The rate constant of the reaction : 2H_(2)O(aq)to2H_(2)O(l)+O_(2)(g) is 3xx10^(-3)min^(-1). At what concentration of H_(2)O_(2), the rate of the reaction will be 2xx10^(-4)M s^(-1) ?

Answer»

`6.67xx10^(-3)M`
`2M`
`4M`
`0.08M`

SOLUTION :Rate `=k[H_(2)O_(2)]`
`2xx10^(-4)=(3XX10^(-3))/(60)xx[H_(2)O_(2)]`
`[H_(2)O_(2)]=4M]`
24804.

The rateconstantof reactionis 5xx10^(-2) "litre " ^(3)"mole"^(-3) "min"^(-1) theorderofreactionis

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`1`
`2`
`3`
`4`

Solution :`k =("rate")/([R]^(N))=(M//s)/(M^(n))=M^(1-n)S^(-1)`
when`n= 4, K= "litre"^(3)"mole" ^(-3) MIN^(-1)`
24805.

The rate constant of reaction, 2A + B rarr C is 2.57xx10^(-5)"L mole"^(-1)sec^(-1) after 10 sec,, 2.65xx10^(-5)"L mol"^(-1)sec^(-1) after 20 sec., and 2.55xx10^(-5)"L mole"^(-1)sec^(-1) after 30 sec. The order of the reaction is :

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0
1
2
3

Answer :C
24806.

The rate constant of raction is 0.2 "min"^(-1). The order of the reaction is

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SECOND
first
zero
third

Solution :The unit of RATE constant of a first ORDER REACTION is `"TIME"^(-1)`.
24807.

The rate constant of reaction is 3xx10^-3atm^-2sec^-1 . The order of reaction is

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1
2
3
0

Answer :B
24808.

The rate constant of n^(th)order reaction has units :

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`LITRE^(1-n)MOL^(1-n)sec^-1`
`mol^(1-n)mol^(1-n)sec^-1`
`mol^(1-n)litre^(n-1)sec^-1`
NONE of these

Answer :C
24809.

The rate constant of nth order has units:

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

Solution :For an nth ORDER reaction : RATE = `K [conc.]^n`
`k = ("rate")/(["conc."]^n)`
Units of `k = (mol L^(-1)s^(-1))/((molL^(-1))^n)= mol^(1-n) L^(n - 1) s^(-1)`
24810.

The rate constant of first order reaction whose half-life is 480 s, is

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`1.44 xx 10^(-3)s^(-1)`
`1.44 s^(-1)`
`0.72 xx 10^(-3)s^(-1)`
`2.88 xx 10^(-3)s^(-1)`

SOLUTION :For the first ORDER REACTION
`implies ""k=(0.693)/(t_(1//2))=(0.693)/(480 sec)=1.44 xx 10^(-3)s^(-1)`
24811.

The rate constant of a first order reaction is 0.60" sec"^(-1). What is its half-life period?

Answer»

SOLUTION :`K=0.50sec^-1`
HALF LIFE PERIOD, `t_(1/2)=0.693/(0.50sec^-1)=1.39 SEC.`
24812.

Derive an expression for the rate constant of first order reaction. The rate constant of first order reaction is 0.346" min"^(-1). What is the half-life?

Answer»

Solution :`K=0.346 min^-1`
HALF life PERIOD`t_(1/2)=0.693/K` or,`t_(1/2)=0.693/(0346min^-1)`=2 MINUTES
24813.

The rate constant of a second order reaction, 2A toProducts, is 10^(-4)" lit mol"^(-1)" min"^(-1). The initial concentration of the reactant is 10^(-2)" mol lit"^(-1). What is the half-life (in min) ?

Answer»

10
1000
100
`10^(6)`

Solution :Half -life period of a second ORDER REACTION
`t_(1//2) = (1)/("Rate CONSTANT" XX "Initial CONC.") = (1)/(ka)`
`=(1)/(10^(-4) L mol^(-1) min^(-1) xx 10^(-2) mol L^(-1))`
` = 10^(6) min`
24814.

The rate constant of a reaction of a reaction increases by 5% whenthe temperature of the reaction is increased from 300 to 301 K wheres equilibrium constant increases only by 2%. Calculate the activation energy for the forward as well as backward reaction.

Answer»

Solution :ACCORDING to Arrhenius EQUATION, `log""(k_(2))/(k_(1))=(E_(a,f))/(2.303"R")((T_(2)-T_(1))/(T_(1)T_(2)))`
If `k_(1)=k" at "300" K, then at "301" K,"k_(2)=k+(5)/(100)k=1.05k`
`:.log""(1.05k)/(k)=(E_(a,f))/(2.303xx8.314" JK"^(-1)MOL^(-1))((301" K"-300" K")/(300" K"xx301" K"))`
`:.E_(a,f)=(log1.05)xx2.303xx(8.314" JK"^(-1)mol^(-1))xx300xx301" (K) "=366554" J mol"^(-1)=36.65" kJ mol"^(-1)`
According to van't Hoff equation (giving the effect of temperature on equilibrium constant),
`log""(K_(2))/(K_(1))=(DeltaH^(@))/(2.303"R")((T_(2)-T_(1))/(T_(1)T_(2)))`
If `K=K_(1)" at "300" K, then at "301" K","K"_(2)="K"+(2)/(100)"K"=1.02" K"`
`:.log""(1.02"K")/("K")=(DeltaH^(@))/(2.303xx8.314" JK"^(-1)mol^(-1))((301"K"-300"K")/(300"K"XX301"K"))`
or `DeltaH^(@)=" Activation energy for forward reaction-Activation energy for backward reaction"=E_(a,f)-E_(a,b)`
`:.E_(a,b)=E_(a,f)-DeltaH^(@)=36.65-14.87" kJ mol"^(-1)=21.78" kJ mol"^(-1).`
24815.

The rate constant of a zero order reaction in A is 0.003 "mol L"^(-1) "sec"^(-1). How long will it take for the initial concentration of A to fall from 0.10M to 0.075 M ?

Answer»

SOLUTION :`t=([A]_0 -[A])/K=(0.10-0.075)/0.003`=8.3 SEC
24816.

The rate constant of a reaction is equal to the rate of reaction when

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Concentration of all REACTANTS are unity
Concentration of all reactants and products are equal
Concentration of reactants and products do not change with TIME
The reaction takes INFINITE time for COMPLETION

Answer :A
24817.

The rate constant of a reaction is independent of

Answer»

temperature
catalyst
cone. of reactant
none of these

Answer :C
24818.

The rate constant of a reaction is equal to rate of reaction

Answer»

when oncentrations of REACTANTS do not CHANGE with time
when concentrations of all reactants and products are equal
at time, t = 0
when oncentrations of all reactants are unity

Solution :If `(dx)/(dt) = k [A]^(X) [ B]^(y) [C]^(z)` for a REACTION , then `(dx)/(dt) = k` When `[A] = 1 = [B]= [C]`
24819.

The rate constant of a reaction is given byk=2.1xx10^10 exp(-2700//RT). It means that

Answer»

log k versus `1/T` will be a straight LINE with SLOPE `=(-2700)/(2.303R)`
log k versus `1/T` will be a straight line withintercepton axis = 10.32
When Tbecomes INFINITE , `k=2.1xx10^10`
k is independent of temperature

Solution :From Arrehenius equation `k=Ae^(-E_(a)//RT)`
Given, `k=2.1xx10^10xxe^(-2700//RT)`

INTERCEPT =log A - log `(2.1xx10^10)`
= 10.32
24820.

The rate constant of a reaction is given by k=2.1xx10^(10)C^(-(2700)/(2.303R) It means that

Answer»

LOG K vs `(1)/(T)` will be straight line with slope `=(-2700)/(2.303R)`
log k vs `(1)/(T)` will be straight line with intercept on log k axis `=log 2.1xx10^(10)`
the NUMBER of effective collisions are `2.1xx10^(10)cm^(-3)sec^(-1)`
half-life of the reaction increases with increase in temperature

Solution :(A) and (B) are correct, (C ) is wrong because frequency factorgives total number of collisions and not the effective collision `cm^(-3)sec^(-1)`, (D) is wrong because half-life of the reaction decreases with increase in temperature (as reaction BECOMES faster)
24821.

The rate constant of a reaction is given by k=2.1xx10^(10)" exp "(-2700/RT) It means that

Answer»

log k vs. `1//T` will be a straight line with slope
`=-(2700)/(2.303" R")`
log k vs. `1//T` will be a straight line with intercept on log k axis `=2.1xx10^(10)`
The number of effective collisions are `2.1xx10^(10)" cm"^(-3)" sec"^(-1)`
Half life of the reaction INCREASES with increase of temperature.

Solution :is wrong because frequency factor gives total number of collicions and not effective collisions `cm^-3 sec^-1`.
(d) is wrng because half - life of the reactions decreases with incerease of temperature ( as reaction BECOMES FASTER ).
24822.

The rate constant of a reaction is doubled when the temperature increased from400K to 410K. Calculate the activation energy (Ea) [R = 8.314 JK^(-1) " mol"^(-1)] .

Answer»

SOLUTION :`log""(k_2)/(k_1) = (E_(a))/(2.303R) [(T_2 - T_1)/(T_1T_2)]`
` log 2 = (E_a)/(2.303 xx 8.314 ) [(410-400)/(400 xx 410)]`
` 0.310 = (E_a)/(19.147)[(10)/(164000)]`
`E_a = (0.301 xx 19.147 xx 164000)/(10)`
`= 94517 "Jmol"^(-1) OR 94.517 "kJmol"^(-1)`
24823.

The rate constant of a reaction is 5.8xx10^(-2)s^(-1). The order of the reaction is ..........

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First order
zero order
SECOND order
Third order

SOLUTION :The UNIT of RATE constant is `s^(-1)` and it indicates that the REACTION is first order.
24824.

The rate constant of a reaction is 5.8xx10^(-2)s^(-1). The order of the reaction is

Answer»

FIRST ORDER
ZERO order
Second order
THIRD order

SOLUTION :The unit of rate constant is `s^(-1)` and it indicates that the reaction is first order.
24825.

The rate constant of a reaction is 2xx10^-5 sec^-1. If the initial concentration is 0.1 M, the initial rate is

Answer»

`2xx10^-4 M sec^-1`
`2xx10^-5M sec^-1`
`2xx10^-6M sec^-1`
`2xx10^-7M sec^-1`

ANSWER :C
24826.

The rate constant of a reaction is 2xx10^(-3)min^(-1) at 300 K temperature .By increase in temperature by 20K,its value becomes three time,then calculate the energy of activation of the reactuon .what will be its rate constant at 310 K temperature?

Answer»

Solution :`E_(a)`=10480 cal,K(310 K)=`3.126xx10^(-3)MIN^(-1)`
24827.

The rate constant of a reaction is 2xx10^(-3) min^(-1) at 300 K temperature .By increase in temperature by 10 K its value becomes doubl. Calculate energy of activation .Calculation the rate constant at 320 K.

Answer»

SOLUTION :`E_(a)`=12810 cal,k(320 K)=`7.659xx10^(-3)min^(-1)`
24828.

The rate constant of a reaction is 2.5xx10^(-2)" L mol"^(-1)s^(-1). Calculate the initial rate with concentration 0.2" mol L"^(-1).

Answer»

Solution :From the units of rate constant,
order of the reaction is 2.
For a SECOND order reaction, rate = k `"[concentration]"^(2)`
Initial rate of the reaction `=2.5xx10^(-2)(0.2)^(2)=1xx10^(-3)" MOL L"^(-1)s^(-1)`
24829.

The rate constant of a reaction is 2.5xx10^-2mole^-1 lit sec^-1. The order of the reaction is

Answer»

zero
1st
2nd
3rd

Answer :C
24830.

The rate constant of a reaction is 2.1xx 10^(-2)mol^(-2)litre^3 min^(-1). The order of reaction is

Answer»

zero ORDER
1
2
3

Solution :UNIT of `K= (mol L^(-1))^(1-n)sec^(-1) or mi n^(-1)` for 3rd order, n = 3
24831.

The rate constant of a reaction is 1.5xx10s^-1 at 100^@C. Calculate the value of activation energy for the reaction.

Answer»

SOLUTION :From RELATION.
`"LOG" K_2/K_1=E_a/(2.303R)[1/T_1-1/T_2]"implieslog"(4.5xx10^7)/(1.5xx10^7)`
`=E_a/(2.303xx8.314)[1/323-1/373]IMPLIES"LOG3"=[E_a//(19.147)]xx50//(323xx373]`
`E_a=(0.4771xx19.147xx323xx373)/50impliesE_a=22.01kj mol^-1`
24832.

The rate constant of a reaction is 1.5xx10^7s^-1 at 50^@Cand 4.5×10^7s^−1 at 100^@C. Calculate the Arrhenius parameter for the reaction.

Answer»

SOLUTION :From RELATION.
`"LOG" K_2/K_1=E_a/(2.303R)[1/T_1-1/T_2]"implieslog"(4.5xx10^7)/(1.5xx10^7)`
`=E_a/(2.303xx8.314)[1/323-1/373]IMPLIES"LOG3"=[E_a//(19.147)]xx50//(323xx373]`
`E_a=(0.4771xx19.147xx323xx373)/50impliesE_a=22.01kj mol^-1`
24833.

The rate constant of a reaction is 1.5 xx 10^(7)s^(-1) at 50^(@)C and 4.5 xx 10^(7) s^(-1) at 100^(@)C. Evaluate the Arrhenius parameters A and E_(a).

Answer»

SOLUTION :Apply Arrhenius.s EQUATION.
`2.19 XX 10^4 J//"mol" , 5.4 xx 10^20 s^(-1)`
24834.

The rate constant of a reaction is 1.2xx10^(-5) "mol"^(-2) "litre"^(2) s^(-1) the order of the reaction is :

Answer»

zero
1
2
3

Answer :D
24835.

The rate constant of a reaction is 0.69 xx 10^(-1) "min"^(-1) and the initial concentration is0.2 mol l^(-1) . The half - life period is

Answer»

400 sec
600 sec
800 sec
1200 sec

Solution :The unit of RATE constant SHOWS that REACTION is of first order . For first order reaction , half life is independent of initial CONC., of the reactant . THUS ,
`t_(1//2) = (0.693)/(0.69 xx 10^(-1)) = (0.693 xx 60)/(0.69 xx 10^(-1)) = 600` sec.
24836.

The rate constant of a reaction is 10.8 xx 10^(-5) mol dm^(-3)s^(-1). The order of the reaction is

Answer»

ZERO
1
2
3

Solution :On the BASISOF UNITS of K, ORDER = zero.
24837.

The rate constant of a reaction has s^-1 units. The reaction is of …..

Answer»

THIRD order
Second order
First order
Zero order

Answer :C
24838.

The rate constant of a reaction has same units as the rate of reaction. The reaction is of …..

Answer»

THIRD ORDER
second order
FIRST order
Zero order

Answer :D
24839.

The rate constant of a reaction depends upon

Answer»

temperature
catalyst
nature of reactant
all of these

Answer :D
24840.

The rate constant of a reaction depend on.

Answer»

Temperature
Mass
Weight
time

Answer :A
24841.

The rate constants of a reaction at 700 K and 760 K are 0.011" M"^(-1)s^(-1) and 0.105" M"^(-1)s^(-1) respectively. Calculate the values of Arrhenius parameters.

Answer»

SOLUTION :`2.824xx10^10`
24842.

The rate constant of a reaction changes when

Answer»

a catalyst is ADDED
concentrations of the REACTANT are changed
TEMPERATURE of changed
both (a) and (c )

Solution :Rate CONSTANT of a reaction changes when either the temperature is changed or catalyst is added.
24843.

The rate constant of a reaction changes with

Answer»

Pressure
Temperature
INITIAL CONCENTRATION of reactants
Extent of REACTION

ANSWER :B
24844.

The rate constant of a reaction at temperature 200K is 10 times than the rate constant at 400K . What is the activation energy (E_(a)) of the reaction (R=gas constant) ?

Answer»

1842.4 R
921.2 R
660.6 R
230.3 R

Answer :B
24845.

The rate constant of a reaction at temperature 200 K is 10 times less than the rate constant at 400K . What is the activation energy (E_(a)) of the reaction (R = gas constant )

Answer»

1842.4 R
921.2 R
460.6 R
230.3 R

ANSWER :B
24846.

The rate constant of a reaction at 500 K and 700 K are 0.02 s^(-1) and 0.07 s^(-1) respectively .Calculate the values of E_(a) and A.

Answer»

SOLUTION :Calculation of `E_(a)`:
`log(K_(2))/(k_(1))=(E_(a))/(2.303 R)((T_(2)-T_(1))/(T_(1)T_(2)))`
`log (0.07 s^(-1))/(0.02 s^(-1))=(E_(a))/(2.303xx8.314 JK^(-1)mol^(-1))xx((700-500)/(700xx500))`
`therefore log 3.5=(E_(a)xx200)/(2.303xx8.314xx700xx500)J mol^(-1)`
`therefore E_(a)(0.5441xx2.303xx8.314xx700xx500)/(200) J mol^(-1)` Calculation of A:
`K=Ae^(-(E_(a))/(RT))`
Where,`E_(a)=18231 J mol^(-1)`
500 K temp.`K_(1)=0.02 s^(-1)`
24847.

The rate constant of a reaction at 400 and 200 K are 0.04 and 0.02s^(-1) respectively. Calculate the value of activation energy .

Answer»

Solution :According the ARRHENIUS equation `log(k_2/k_2)=E_a/(2.303R)((T_2-T_1)/(T_1T_2))`
`T_2 =400K , k_2=0.04s^(-1)`
`T_1=200K , k_1=0.02s^(-1)`
`log(0.04s^(-1)/(0.02s^(-1)))=(E_a)/(2.303xx8.314"J K "^(-1) MOL^(-1))((400K-200K)/(200Kxx400K))`
`log(2)=E_a/(2.303xx8.314" J K "^(-1)mol^(-1))((1)/(400K))`
`E_a=log(2)xx2.303xx8.314"JK "^(-1)"mol"^(-1)xx400K`
`E_a=2305"J mol"^(-1)`
24848.

The rate constants of a reaction at 500 K and 700 K are 0.02s^(-1) and 0.07s^(-1) respectively. Calculate the values of E_(a) and A.

Answer»

SOLUTION :`18.23 "KJ MOL"^(-1)`, 1.603
24849.

The rate constant of a reaction at 200K is 10 times less than rate constant at 400K. Value of E_a? [R = gas constant]

Answer»

`1842.4` R
`921.2` R
`460.6` R
`230.3` R

Answer :B
24850.

The rate constant of a raction at 500 K and 700 K are 0.02 s^(-1) and 0.07s^(-1) respectively. Calculate the value of E_(a)

Answer»

SOLUTION :18.230 KJ