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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1151. |
Unit of first order rate constant isA. `mol dm^(-3)"time"^(-1)`B. `dm^(-3)mol^(-1)"time"^(-1)`C. `"time"^(-1)`D. `mol ,dm^(3),"time"^(-1)` |
| Answer» Correct Answer - C | |
| 1152. |
`Zn+2H^(o+)rarrZn^(2+)+H_(2)` The half-life periof is independent of the concentration of zinc at constant `pH`. For the constant concentration of `Zn`, the rate becomes `100` times when `pH` is decreased form `3` to `2`. Hence,A. `(dx)/(dt) = k[Zn]^(0)[H^(o+)]^(2)`B. `(dx)/(dt) = k[Zn][H^(o+)]^(2)`C. Rate is not affected if the concentration of zinc is made four times and that of `H^(o+)` ion is halved.D. (d) Rate becomes four times if the concentration of `H^(o+)` ion is doubled at constant `Zn` concentration. |
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Answer» Correct Answer - B::C::D (i) Since `t_(1//2)` is independent of concentration of `Zn` at constant `pH` means that the order w.r.t. `[Zn] =1`. (ii). Le `r_(1) prop [H^(o+)]^(x) rArr r_(1) prop [10^(-3)]^(x)` , [when `pH = 3`] `r_(2) = 100r_(1) prop[10^(-2)]^(x)` , [when `pH = 2`] Thus, `(r_(2))/(r_(1)) = [(10^(-2))/(10^(-3))]^(x)` `100 = (10)^(2) = [10]^(x) rArr x = 2` Hence, order w.r.t. `[H^(o+)] = 2` (b) Hence, the rate `= ((dx)/(dt)) = k[Zn][H^(o+)]^(2)` So (b) is the correct answer. ( c) `((dx)/(dt)) = r_(1) = k[Zn][H^(o+)]^(2)` `r_(2) = k[Zn][(H^(o+))/(2)]^(2)` Thus, `r_(2) = r_(1)` (d) `r_(1) = k[Zn][H^(o+)]^(2)` ...(i) `r_(2) = k[Zn][2H^(o+)]^(2)` ...(ii) Divide (ii) by (i), `r_(2) = 4r_(1)` |
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| 1153. |
The rate of a reaction that not involve gases is not dependent onA. PressureB. TemperatureC. ConcentrationD. Catalyst |
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Answer» Correct Answer - a The rate of reaction depends upon conc., of reactant , surface area of reactant , temperature , presence of light and catalyst . |
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| 1154. |
For the reaction `2NO_(2)rarr2NO+O_(2)`, rate expressed as :A. `-(1)/(2)(d[NO_(2)])/(dt)=(1)/(2)(d[NO])/(dt)=(d[O_(2)])/(dt)`B. `-(1)/(2)(d[NO_(2)])/(dt)=-(1)/(2)(d[NO])/(dt)=(d[O_(2)])/(dt)`C. `-(2d[NO_(2)])/(dt)=(2d[NO])/(dt)=(d[O_(2)])/(dt)`D. `-(d[NO_(2)])/(dt)=(d[NO])/(dt)=(d[O_(2)])/(dt)` |
| Answer» Correct Answer - B | |
| 1155. |
Half life `(t_(1/2))` of first order reaction isA. dependent of concentrationB. independent of concentrationC. dependent of timeD. dependent of molecularity |
| Answer» Correct Answer - B | |
| 1156. |
The rate of reaction increases with rise in temerature because of :A. increase in the number of activated molecules.B. increase in the activation energyC. decrease in the activation energyD. increase in the number of the molecular collisions |
| Answer» Correct Answer - D | |
| 1157. |
The rate of reaction that does not involve gases, is not depend on :A. prssrureB. temepratureC. concentrationD. catalyst |
| Answer» Correct Answer - A | |
| 1158. |
`Zn+2H^(+)toZn^(2+)+H_(2)` Half-life period is independent of concentration of zinc at constant pH. For the constant concentraio of Zn, rate becomes `100` times when pH is decreased from 3 "to" 2. Hence,A. `(dx)/(dt)=k[Xn]^(0)[H^(+)]^(2)`B. `((dx)/(dt))=k[Zn][H^(+)]^(2)`C. rate is not affected if connentration of zinc is made fourn times and that of `H^(+)` ion is halvedD. rate becomes four times if concentration of `H^(+)` ions is doubled at constant Zn concentration. |
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Answer» Correct Answer - B::C::D |
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| 1159. |
Rate constant does not depend upon unit of concentration for reaction whose order isA. zeroB. firstC. fractionalD. infinite |
| Answer» Correct Answer - B | |
| 1160. |
Half life of reaction `: H_(2)O_(2)(aq) rarr H_(2)O(l)+(1)/(2)O_(2)(g)`is independent of initial concentration of `H_(2)O_(2)` volume of `O_(2)` gas after 20 minute is `5L` at `1 atm` and `27^(@)C` and after completion of reaction is `50L`. The rate constant is `:`A. `(1)/(20)log 10 mi n^(-1)`B. `(2.303)/(20)log 10 mi n^(-1)`C. `(2.303)/(20)log. (50)/(45)mi n^(-1)`D. `(2.303)/(20)log. (45)/(50)mi n^(-1)` |
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Answer» Correct Answer - 3 `t_(1//2)` is independent of initial concentration a, for first order reaction `x alphaV_91)(=5L` at `t=20` minutes ) `a prop V_(1)(=50L` at completion) `k=(2.303)/(t)log.(a)/(a-x)log.(50)/(45)` |
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| 1161. |
Unit of rate of reaction isA. `mol dm^(-3) "time"^(-1)`B. `mol^(-1) dm^(3) "time "^(-1)`C. `mol dm ^(-3)`timeD. `mol^(-1)dm^(-1) "time"^(-1)` |
| Answer» Correct Answer - A | |
| 1162. |
Which of the following is a first order reaction ?A. `2HIrarrH_(2)+I_(2)`B. `2NO_(2)rarr2NO+O_(2)`C. `2NO+O_(2)rarr2NO_(2)`D. `NH_(4)NO_(2)rarrN_(2)+2H_(2)O` |
| Answer» Correct Answer - D | |
| 1163. |
For first order reaction, the half life is independent of :A. initial concentrationB. cube root of initial concentrationC. first power of initial concentrationD. square root of final concentration |
| Answer» Correct Answer - A | |
| 1164. |
Which one of the following is not a first order reaction?A. `CH_(3)COOCH+H_(2)Ooverset(H^(+))rarrCH_(3)OH`B. `CH_(3)COOCH_(2)H_(5)+NaOHrarrCH_(3)COONa+C_(2)H_(5)OH`C. `2H_(2)O_(2)rarr 2H_(2)O+O_(2)`D. `2N_(2)O_(5)rarr4NO_(2)+O_(2)` |
| Answer» Correct Answer - B | |
| 1165. |
Rate expression of a chemical change is `-(dx)/(dt)=k[A]^(2)[B]^(1)[C]^(0)` The order of reaction is :A. 3B. 2C. 1D. zero |
| Answer» Correct Answer - A | |
| 1166. |
If the rate expression for a reaction is `(dx)/(dt)=k[A]^(1//2)[B]^(2//3)`, the overall order of the reaction is :A. 2B. `1//2`C. `3//2`D. 1 |
| Answer» Correct Answer - A | |
| 1167. |
For the reaction, `2NOrarrN_(2)+O_(2)`, the expression `-(1)/(2)(d[NO])/(dt)` represents:A. the rat of formation of NOB. the average rate of the reactionC. the instantaneous rate of the reactionD. all of the above |
| Answer» Correct Answer - C | |
| 1168. |
`aB+bBrarrP,dxx//dt=k[A]^(a)8[B]^(b)`. If conc. of A is doubled, rate is doubled. If B is doubled, rate becomes four times. Which is corect?A. `(-d[A])/(dt)=(-d[B])/(dt)`B. `(-d[A])/(dt)=(-2d[B])/(dt)`C. `(-2d[A])/(dt)=(-d[B])/(dt)`D. None of these |
| Answer» Correct Answer - C | |
| 1169. |
In the reaction `3Ararr2B`, rate of reaction `+(d[B])/(dt)` is equal to :A. `(1)/(3)(d[A])/(dt)`B. `(2)/(3)(d[A])/(dt)`C. `+2(d[A])/(dt)`D. `(3)/(2)(d[A])/(dt)` |
| Answer» Correct Answer - B | |
| 1170. |
In a reaction `2A_(2)+B_(2)rarr2A_(2)B,` the reactant A will desapper at :A. half the rate that B will decreaseB. the same rarte that B will decreaseC. double the rate that `A_(2)B` will fromD. twice the rate that B will deceases |
| Answer» Correct Answer - D | |
| 1171. |
The rate constant `k`, for the reaction `N_(2)O_(5)(g) rarr 2NO_(2) (g) + (1)/(2) O_(2)(g)` is `2.3 xx 10^(-2) s^(-1)`. Which equation given below describes the change of `[N_(2)O_(5)]` with time ? `[N_(2)O_(5)]_(0)` and `[N_(2)O_(5)]_(t)` correspond to concentration of `N_(2)O_(5)` initially and at time, `t` ?A. `[N_(2)O_(5)]_(t) = [N_(2)O_(5)]_(0) + kt`B. `[N_(2)O_(5)]_(0) = [N_(2)O_(5)]_(t)e^(kt)`C. `log_(10) [N_(2)O_(5)]_(t) = log_(10) [N_(2)O_(5)]_(0) - kt`D. In `([N_(2)O_(5)]_(0))/([N_(2)O_(5)]_(t)) = kt` |
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Answer» Correct Answer - D Rate constant `= 2.3 xx 10^(-2) sec^(-1)` It means it is a first order reaction (because unit of rate constant is `sec^(-1)`) For first order reaction`K = (1)/(t)ln(a)/(a-x)` `Kt = ln(a)/(a-x) = ln[N_(2)O_(5)]_(0)/([N_(2)O_(5)]_(x)` |
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| 1172. |
Which of the following isotopes will shows radioactive disintegration?A. `._(83)Bi^(209)`B. `._(82)Bi^(210)`C. `._(6)C^(12)`D. `._(82)Pb^(206)` |
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Answer» Correct Answer - B |
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| 1173. |
If the rate constant for the disintegration of a radioactive nucleus is `lambda`. Therefore the probability, `P` of survival of a radioactive nucleus for one mean life isA. `e`B. ( b) `e^(2)`C. `e^(-1)`D. `e^(-2)` |
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Answer» Correct Answer - C Probability for survival `= (N)/(N_(0)) = e^(-lambda ul(t))` Now mean life period `= (1)/(lambda)` `:.` Probability `= e ^(-lambda xx (1)/(lambda)) = e^(-1)` |
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| 1174. |
The rate of reaction can be increased in general by all the following factors exceptA. by increasing the temperatureB. using a suitable catalystC. by increasing the concentration of reactantsD. by an increase in activation energy |
| Answer» Correct Answer - D | |
| 1175. |
For the reaction,`A+Brarr2C+D`, which one is the incorrect statement?A. Rate of disappearance of A = Rate of disappearace of BB. Rate of disappearance of A = Rate of disappearace of DC. Rate of disappearance of `B =2xx` rate of disappearace of CD. Rate of disappearance of `B=(1)/(2)xx` rate of disappearace of C |
| Answer» Correct Answer - C | |
| 1176. |
The rate constant of a reaction does not depend upon:A. temperatureB. activation energyC. calalystD. concentration of reactants and products |
| Answer» Correct Answer - D | |
| 1177. |
Radioactive disintegration is a `……………….` order reaction.A. zero order reactionB. first order reacationC. second order reactionD. third order reaction |
| Answer» Correct Answer - B | |
| 1178. |
Which of the follwing statement is not correct for the reaction, `4A+Brarr2C+2D?`A. The rate of appearance of C is one-half the rate of disappearance of B.B. The rate of disappearance of B is one-half the rate of disappearance of B.C. The rate of formation of D is one-half the rate of disappearance of B.D. The rates of formation of C and D are equal |
| Answer» Correct Answer - A | |
| 1179. |
The rate constant of a reaction does not depend upon:A. tempertureB. activation energyC. catalystD. concentration of reactants and products |
| Answer» Correct Answer - D | |
| 1180. |
If reaction between A and B to give C shows first order kinetics in A and second order in B, the rate equation can be written asA. Rate = `k [A] [B]^(1//2)`B. Rate = `k [A]^(1//2) [B]`C. Rate = `k [A] [B]^(2)`D. Rate = `k [A]^(2) [B]` |
| Answer» Correct Answer - c | |
| 1181. |
The overall rate of a reaction is governed by :A. the rate of the fastest intermediate stepB. the sum total of the rates of all the intermediate stepsC. the average of the slowest of all the intermediate stepD. the rate of the slowest intermediate step |
| Answer» Correct Answer - D | |
| 1182. |
The overall rate of a reaction is governed by :A. the rate of the fastest is governed byB. the rate of the slowest intermediate stepC. the sum total of the rates of all the intermediate stepsD. the average of the rates of all the intermidiates steps |
| Answer» Correct Answer - B | |
| 1183. |
For a hypothetical reaction ` A + B to ` products The rate law is `, R = R[A]^(@) [B]` , The order of reaction isA. 1B. 2C. 1.5D. Zero |
| Answer» Correct Answer - a | |
| 1184. |
If reaction between A and B to give C shows first order kinetics in A and second order in B, the rate equation can be written asA. Rate = `k [A] [B]^(1//2)`B. Rate = `k [A]^(1//2) [B]`C. Rate = `k [A] [B]^(2)`D. Rate = `k [A]^(2) [B]` |
| Answer» Correct Answer - c | |
| 1185. |
The overall rate of a reaction is governed by :A. Slowest stepB. Fastest stepC. Sum of rate of all stepsD. Molecularity of all steps |
| Answer» Correct Answer - a | |
| 1186. |
In hydrolysis of organic cholride with excess of water `RCl+H_(2)OtoROH+HCl`A. Molecularity is 2 , order of reaction is also 2B. Molecularity is 2 , order of reaction is 1C. Molecularity is 1 , order of reaction is 2D. Molecularity is 1 , order of reaction is also1 |
| Answer» Correct Answer - b | |
| 1187. |
Consider the following statements. i) Increase in concentration of rectant increases the rate of a zero order reaction. ii) rate constant k is equal to collision frequency a if `E_(a)=0` iii) rate constant k is equal to collision frequency A if `E_(a) = infty`. iv) In k vs T is a straight line. v) In k vs `1//T` is a straight line. Correct statements are:A. i) and iv)B. ii) and v)C. iii) and iv)D. ii) and iii) |
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Answer» Correct Answer - B i) For zero order reaction the increases in concentration of reactants does not affect reaction rate. ii) According to Arrhenius equation. `k=Ae^(-Ea//RT)` Where `E_(a) =0, k=A` iii) When `E_(a) = infty, klt A` iv) In k vs t is not a straight line v) In k vs `1//T` is a straight line with slope `=(-Ea//R)` Statements (ii) and (v) are `DeltaH` correct. |
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| 1188. |
For a reaction taking place in three steps , the rate constants are `k_(1) , k_(2)` and `k_(3)` . The overall rate constant `k = (k_(1) k_(2))/(k_(3))` . If the energy of activation values for the first , second and third stages are respectively 40 , 50 , and 60 kJ `mol^(-1)`, then the overall energy of activation in kJ `mol^(-1)` isA. 30B. 40C. 60D. 50 |
| Answer» Correct Answer - a | |
| 1189. |
For a reaction taking place in three steps, the rate constant are `k_(1), k_(2)` and `k_(3)` and overall rate constant is `k=(k_(1)k_(3))/(k_(2)`. If the energies of activation `E_(1)`, `E_(2)` and `E_(3)` are 60, 30 and 10 kJ `mol^(-1)` respectively, then the overall energy of activation is:A. 30 kJ `mol^(-1)`B. 40 kJ `mol^(-1)`C. `60 kJ mol^(-1)`D. `100 kJ mol^(-1)` |
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Answer» Correct Answer - B According to the available information. `k_(1) = A_(1)e^((-Ea)//Rt)` `k_(2) = A_(2)e^((-Ea)//RT)` `k_(3) = A_(3)e^((-Ea)//RT)` `k = (k_(1)k_(3))/(k_(2)) - [E_(a1)+E_(a3) - E_(a2)]` `=(k_(3)k_(2))/(k_(2)) = (A_(1)A_(3))/(A_(2))e` `=E_(a) ("total") = E_(a1)+E_(a3)-E_(a2)` `=60 + 10-30=40 kJ mol^(-1)` |
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| 1190. |
The branch of chemistry which deals with the reaction rates and reaction mechsnism is calledA. ThermochemistryB. PhotochemistryC. Analytient chemistryD. Chemical Kinetics |
| Answer» Correct Answer - D | |
| 1191. |
Why does liquid bromine reacts slowly as compared to vapours of bromine? |
| Answer» In the vapour state, the molecules of bromine have more kinetic energy than in the liquid state. Therefore, collisions with the molecules of other reactants in the vapour state will be faster than in the liquid state. Moreover, in the vapour state, the surface area available for the chemical reaction is more as compared to the liqiud state. Hence, bromine in the vapour state reacts at a faster rate compared with the liquid state. | |
| 1192. |
What is half life period ? Calculate the half life period for zero order reaction. |
| Answer» half life period `(t_(1//2))` is the time taken to complete half of the reaction. | |
| 1193. |
A reaction proceeds with a uniform rate throughout. What do you conclude? |
| Answer» If a reaction proceeds at a uniform rate throughout, this means that the reaction rate is not affected by change to concentration of the reactants. The reaction is of zero order. | |
| 1194. |
In a multi-step reaction, the rate is determined by conisdering the………….step. |
| Answer» The slowest step in the reaction is the rate determing step. | |
| 1195. |
The rate of the reaction: `CH_(3)COOC_(2)H_(5) + NaOH to Ch_(3)COONa + C_(2)H_(5) OH` is given by the equation, rate `= k [CH_(3) COOC_(2)H_(5)][NaOH]` If concenration is expressed in mol/L the units of k areA. `mol^(-2) L^(2) s^(-1)`B. `mol L^(-1) s^(-1)`C. `L mol^(-1) s^(-1)`D. `S^(-1)` |
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Answer» Correct Answer - C For a second order reaction, `(dx)/(dt) = k [A]^(2)` `("conc.")/("time") = k [conc.]^(2)` `(mol L^(-1))/(s) = k mol L^(-1) xx mol L^(-1)` `k = L mol^(-1) s^(-1)` |
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| 1196. |
For a general reaction `X to Y`, the plot of conc. Of X vx time is given in the figure. What is the order of the reaction and what are the units of rate constant? A. zero, mol `L^(-1) s^(-1)`B. First, mol `L^(-1) s^(-1)`C. First, `s^(-1)`D. Zero, L `mol^(-1) s^(-1)` |
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Answer» Correct Answer - A For a zero order reaction, rate `= k = (dx)/(dt)` Unit of `k = mol L^(-1) s^(-1)` |
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| 1197. |
For the hypothetical reaction, `A rarr` Products, rate `=-k[A]` The negative sign used in the rate expression indicate that |
| Answer» In order to make reaction rate positive. | |
| 1198. |
In any unimolecular reactionA. the order and molecularity of the slowest step are equal to oneB. molecularity of the reaction can be zero, one or one stepC. more then one reacting species are involved in one stepD. molecularity of the reaction can be determined only experimentally. |
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Answer» Correct Answer - A For a unimolecular reaction, both order and molecularity are one in rate determining step. |
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| 1199. |
The reaction `2X to Y + Z` would be zero order reaction whenA. rate remains unchanged at any concentration of Y and ZB. rate of reaction doubles if concentration of Y is doubledC. rate of reaction remains same at any concentration of XD. rate of reaction is directly proportional to square of concentration of X |
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Answer» Correct Answer - C Rate of a zero order reaction is independent of the concentration of reactants. |
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| 1200. |
The overall rate of a reaction is governed by :A. the rate of fastest intermediate stepB. the sum of the rates of all intermediate stepsC. the average of the rates of all the intermediate stepsD. the rate of slowest intermediate step. |
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Answer» Correct Answer - D The slowest step is rate determining step. |
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