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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.
| 1801. |
For the reaction `2H_(2)+O_(2)rarr 2H_(2)O`, the rate law expression is , `r = k[H_(2)]^(n)`. When the concentration of `H_(2)` is doubled, the rate of reaction found to be quadrupled. The value of n is |
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Answer» Correct Answer - C `r=k[H_(2)]^(n)` On doubling the concentration of `H_(2),` `4r=k[2H_(2)]^(n)` On dividing Eq. (ii) by (i) , we get, `4=2^(n)` `(2)^(2)=(2)^(n)rArrn=2` |
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| 1802. |
Powdered magnesium element catches fire more repidly than magnesium wire of the same mass becauseA. Surface area of magnesium wire is larger than their powdered formB. density of magnesium wire is greater than that of their powdered formC. powdered magnesium have larger surface areaD. None of above |
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Answer» Correct Answer - C The rate of a reaction increases with iincrease in their surface area. |
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| 1803. |
A nuclear explosion has taken place leading to increase in concentration of `C^(14)` in nearby areas. `C^(14)` concentration is `C_(1)` in nearby areas and `C_(2)` in areas far away. If the age of the fossil is determind to be `T_(1) and T_(2)` at the places respectively thenA. the age of fossil will increase at the place where explosion has taken place and `T_(1)-T_(2) = 1/lambda In C_(1) /C_(2)`B. the age of fossil will decrease at the place where explosion has taken place and `T_(1)-T_(2) = 1/lambda In C_(1) /C_(2)`C. the age of fossil will be determined to be the sameD. `T_(1)/T_(2) = C_(1) / C_(2)` |
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Answer» Correct Answer - a |
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| 1804. |
What should be the age of fossil for meaningful determination of its age?A. 6yrB. 6000 yrC. 60,000 yrD. It can be used to calculate any age |
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Answer» Correct Answer - b |
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| 1805. |
which of the following option is correct?A. In living organisms, circulation of `^14C`from atmosphere is high so the carbon content is content in organismB. Carbon dating can be used to find out the age of earth crust and rocksC. Radioactive absorption due to cosmic radiation is equal to the rate of radioactive decay, hence the carbons content remains constant in living organismsD. Carbon dating cannot be used to determine concentration of `^14C` in dead beings |
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Answer» Correct Answer - c |
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| 1806. |
A catalystA. increases the average kinetic energy of reacting moleculesB. decreases the activation energyC. alters the reaction mechanismD. increases the frequency of collisions of reacting species |
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Answer» Correct Answer - b,c |
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| 1807. |
The rate constant of the reaction `A rarr B` is `0.6 xx 10^(-3)` mole per second. If the concentration of `A` is `5 M`, then concentration of `B` after `20` minutes is:A. 3.60 MB. 0.36 MC. 0.72 MD. 1.08 M |
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Answer» Correct Answer - C c) The units of rate constant suggest that the reaction is of zero order. The reaction rate is independent of concentration. Concentration of B `=k xxt` `=(0.6 xx 10^(-3) mol L^(-1)s^(-1)) xx (20 xx 60)s` `=0.72 mol L^(-1) = 0.72M`. |
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| 1808. |
The rate constant of the reaction `A rarr B` is `0.6 xx 10^(-3)` mole per second. If the concentration of `A` is `5 M`, then concentration of `B` after `20` minutes is:A. `0.36M`B. `0.72M`C. `1.08M`D. `3.60M` |
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Answer» Correct Answer - B Units of rate constant indicate that it is a zero order reaction. Its integrated rate law is `x=kt` where `x` is the concentration of product at time `t` . Substituting the values, we get `x=(0.6xx10^(-3)mole//L.s)(2.0min)((60s)/(min))` `=0.72mol//L` or `0.72M` |
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| 1809. |
For the reaction system `2NO(g) + O_(2)(g) rarr 2NO(g)` volume is suddenly produced to half its value by increasing the pressure on it. If the reaction is of first order with respect to `O_(2)` and second order with respect to `NO`. The rate of reaction willA. diminish to one-eighth of its reaction wilB. Increase to eight times of its initial value.C. Increase to four times of its initial value.D. diminish to one-fourth of its initial value. |
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Answer» Correct Answer - B b) Rate ( r) = `k[NO]^(2)[O_(2)]` When the volume is reduced to half `(1//2)`, the concentration will become double. New rate ( r) = `k[2NO]^(2)[2O_(2)]` `=8k[NO]^(2)[O_(2)]` New rate will be 8 times the old rate. |
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| 1810. |
For the reaction system `2NO(g) + O_(2)(g) rarr 2NO(g)` volume is suddenly produced to half its value by increasing the pressure on it. If the reaction is of first order with respect to `O_(2)` and second order with respect to `NO`. The rate of reaction willA. increase to four times of its initial valueB. increase to eight times of its initial valueC. diminish to one-eight of its initial valueD. diminish to one-fourth of its initial value |
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Answer» Correct Answer - B We have `Rate_(1)=k[NO]^(2)[2O_(2)]` or, `(Rate_(2))/(Rate_(1))=(k[2NO]^(2)[2O_(2)])/(k[NO]^(2)[O_(2)])=8` i.e., `Rate_(2)=8Rate_(1)` The rate of reaction will increase to eight time of its initial rate if the volume of the reaction vessel is doubled |
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| 1811. |
Assertion (A) : Poistive catalysts increase the rate of reaction. Reason (R ): Catalysts decrease the value of `DeltaG^(ɵ)`.A. If both `(A)` and `(R )` are correct, and `(R )` is the correct explnation of `(A)`.B. If both `(A)` and `(R )` are correct, but `(R )` is noth the correct explanation of `(A)`.C. If `(A)` is correct, but `(R )` is incorrect.D. If `(A)` is incorrect, but `(R )` is correct. |
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Answer» Correct Answer - C Catalysts does not alter the value of `DeltaG`.Correct Answer - C Catalysts does not alter the value of `DeltaG`. |
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| 1812. |
The rate constant of the reaction `A rarr B` is `0.6 xx 10^(-3)` mole per second. If the concentration of `A` is `5 M`, then concentration of `B` after `20` minutes is:A. `0.36 M`B. `0.72 M`C. `1.08 M`D. `3.60 M` |
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Answer» Correct Answer - B For zero order reaction: `x = K.t` `= 0.6 xx 10^(-3) xx 20 xx 60` `x = 0.72 M` |
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| 1813. |
A catalysts is usedA. Only for increaisng the velocity of a reactionB. For altering the velocity of a reactionC. Only for decreaisng the velocity of a reactionD. All (a), (b), and (c ) are correct |
| Answer» Correct Answer - B | |
| 1814. |
The addition of a catallystic during a chemical reaction alters which of the following quantities ?A. Activation energyB. EntropyC. Internal energyD. Ethalpy |
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Answer» Correct Answer - A The catalyst provides an alternate pathway or reaction mechanism by reducing the activation energy between reactants and products and hence lowering the potential energy barrier. |
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| 1815. |
For the first order reaction,A. the degee of dissociations is equal to `(1 - e^(-kt))`B. a plot of reciprocal concentration of the reactant vs time gives a straight lineC. the time taken for the completion of 75% reaction is thrice the `1/2` of the reactionD. the pre- exponential factor in the Arrhenius equction has the dimension of time , `T^(-1)` |
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Answer» Correct Answer - a,d |
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| 1816. |
Which one of the following statements for the order of a reaction is incorrect ?A. Order of reaction is always whole numberB. Order can be determined by only experimentally .C. Order is not influenced by stoichoiometric coefficient of the reactant .D. Order of reaction is sum of of power of concentration terms or reactants to express the rate of reaction |
| Answer» Correct Answer - A | |
| 1817. |
the following statement (s) is are correctA. A plot of log ` K_(p) vs1/p` is linearB. A plot of log [X] vs time is linear for a first order reaction , `X to P`C. A plot of log `p vs 1/T` is linear at constant volumeD. A plot of `p vs 1/V` is livear at constant temperature |
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Answer» Correct Answer - a,b,d |
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| 1818. |
The correct statement regarding the functioining of a catalyst is that it : `Irarr` alters the energy lelvels of the reactants and products `IIrarr` provides an alternae path for climbing the activation energy barrier `IIIrarr` makes the reacton thermodynamically feasible `IVrarr` provides a different mechanism for the reactionA. I and IIB. I and IIIIC. II and IVD. III and IV |
| Answer» Correct Answer - C | |
| 1819. |
According to the Arrhenius equationA. A high activation energy usually implies a fast reactionB. Rate constant increases with increase in temperature . This is due to a greater number of collisions whose energy exceeds the activation energyC. Higher the magnitude of activation energy , stronger is the temperature dependence of the rate constantD. The pre-exponential factor is a measure of the rate at which collisions occur , irrespective of their energy |
| Answer» Correct Answer - bcd | |
| 1820. |
An example of autocatalytic reaction isA. Decompoistion of nitroglycerineB. Thermal decompoistion of `KClO_(3)` and `MnO_(2)` mixtureC. Breakdown of `.^(14)C_(6)`D. Hydrogenation of vegetable oil uisng nickel catalysts |
| Answer» Correct Answer - B | |
| 1821. |
According to the Arrhenius equation,A. a high activation energy usually implies a fast reaction.B. rate constant increases with increases in temperature. This is due to a greater number of collisions whose energy exceeds the activation energy.C. higher the magnitude of activation energy, strongest is the temperature dependencies of the rate constant.D. the pre-exponential factor is a measure of the rate at which collisions occur, irrespective of their energy. |
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Answer» Correct Answer - B::C::D (b,c,d) options (b,c,d) are correct. Option (a) is wrong because high activation energy usually implies a slow reaction. |
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| 1822. |
For the first order reaction `2N_(2)O_(5)(g) rarr 4NO_(2)(g) + O_(2)(g)`A. the concentration of the reactant decreases exponentially with timeB. the half - life of the reaction decreaases with increasingC. the half- life of the reaction decreases with increasing temperatureD. the half - life of the reaction deponds on the initial concentration of the reactant |
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Answer» Correct Answer - a,b,d |
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| 1823. |
Which of the following statement regarding catalyst is not true?A. A catalyst remains unchanged in compoistion and quantity at the end of the reaction.B. A catalyst can initiate a reaction.C. A catalyst does not alter the equilibrium in a reverisble reaction.D. Catalysts are sometimes very specific in respect of reaction. |
| Answer» Correct Answer - B | |
| 1824. |
According to the Arrhenius equctionsA. a high acitvation energy usually implies a fast reactionB. rate constant increases with increase in temperature. This is due to a greater number of collisions whose energy exceeds the activation energyC. higher the magnitude ofa activation energy. Stronger is the temperature dependence of the rate constantD. the pre- exponential factor is a measure of the rate at which collisions occur, irrespective of their energy collisions occur, irrespective of their energy |
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Answer» Correct Answer - b,c,d |
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| 1825. |
In a bimolecular reaction, the steric factor P was experimentally determined to be 4.5. The correct options among the following is (are):A. The value of frequecny factor predicted by Arrhenius equation is higher thatn that determined experimentallyB. The activation energy of the reaction is unaffected by the value of the steric factorC. Since P=4.5 the reaction will not proceed unless an effective catalyst is addedD. Experimentally determined value of frequecny factor |
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Answer» Correct Answer - B::D Activation energy of a reacton does not depend on the value of steric factor `Pgt` 1 shows that `A_("cal")ltA_("exp")`. Here `A_("cal")` = Calcualated frequency factor using Arrhenius equation `A_("exp")` = Experimentally determined fequency factor |
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| 1826. |
In a bimolecular reaction, the steric factor P was experimentally determined to be 4.5. The correct options among the following is (are):A. The activation energy of the reaction is unaffected by the value of the steric factor.B. Experimentally determined value of frequency factor is higher than that predicted by Arrhenius equation.C. The value of frequency factor predicted by Arrhenius equation is higher than that determined experimentally.D. Since, P=4.5, the reactions will not proceed unless an effective catalyst is used. |
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Answer» Correct Answer - A::B (a,b) Activation energy of the reaction is unaffected by the value of steric factor (P). Steric factor = `(A_("experimental"))/(A_("calculated"))` (A represents frequency factor) Since steric factor is quite high (4.5), This means that `A_("exponential")` is higher than `A_("calculated")` i.e., `A_("experimental") gt A_("calculated")` is higher than `A_("calculated")` i.e., |
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| 1827. |
Mark the correct statement in a reverisble reaction.A. A catalyst catalyzes the forward reaction.B. A catalyst catalyzes the backward reaction.C. A catalyst influences a direct and a reverse reaction to the same extent.D. A catalyst increases the rate of forward reaction and decreases the rate of backward reaction. |
| Answer» Correct Answer - C | |
| 1828. |
In a bimolecular reaction. The steric factor P was experimentally determined to be 4.5. the correct option(s) among the following is (are)A. The activation energy of the reaction is unaffected by the value of the steric factor.B. Experimentally determined value of frequency factor is higher than that predicated by Arrhenius equcationC. The value of frequency factor predicated by Arrhenius equction is higher than that determined experimentallyD. Since P= 4.5, the reaction will not proceed uncles as effective catayst is used |
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Answer» Correct Answer - a,c |
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| 1829. |
The second order rate constant is usually expressed asA. `Mol L s^(-1)`B. `Mol^(-1) L^(-1) s^(-1)`C. `Mol L^(-1) s^(-1)`D. `Mol^(-1) L s^(-1)` |
| Answer» Correct Answer - D | |
| 1830. |
The rate constant of a reaction depends onA. temperatureB. intial concentration of the reactantsC. time of reactionD. extent of reaction |
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Answer» Correct Answer - a |
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| 1831. |
A catalyst onlyA. Increases the free energy change in the reactionB. Decreases the free energy change in the reactionC. Does not increase or decrease the free energy change in the reactionD. Can either increase or decrease the free energy change depending order rate what catalyst we use |
| Answer» Correct Answer - C | |
| 1832. |
In a second order reaction, the plot of `1//(a-x)` versus `t` is a straight line. |
| Answer» Correct Answer - T | |
| 1833. |
The specific rate constant of a first order reaction depends on theA. concentration of the reactantsB. concentration of the productsC. timeD. temperature |
| Answer» Correct Answer - D | |
| 1834. |
The specific rate constant of a first order reaction depends on theA. TemperatureB. MassC. WeightD. Time |
| Answer» Correct Answer - A | |
| 1835. |
The specific rate constant of a first order reaction depends on theA. concentration of the reactantB. concentration of productC. timeD. temperature |
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Answer» Correct Answer - D At any given temperature the value of rate constant is fixed it is independent of initial concentration of reactants, time of reaction , extent of reaction etc. |
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| 1836. |
The specific rate constant of a first order reaction depends on theA. Concentration of the reactantB. Concentration of the ProductC. TimeD. Temperature |
| Answer» Correct Answer - D | |
| 1837. |
The following reaction was carreid at 300 K. `2SO_(2)(g) + O_(2)(g) ltimplies 2SO_(3)(g)` The concentration of `SO_(3)` gas is `5.0 xx 10^(-3)` moles after 7.5 minutes of the start of the reaction. Calcualte the average rate of formation of `SO_(3)` during the reaction. |
| Answer» Average rate of formation of `SO_(3) = (5 xx 10^(-3)mol)/(7.5 min) = 6.67 xx 10^(-4) mol min^(-1)` | |
| 1838. |
The role of a catalyst is to change……….A. Gibbs energy of reactionB. enthalpy of reactionC. activation energy of reactionD. equilibrium constant |
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Answer» Correct Answer - C The role of a catalyst is to change is to the acvtivation energy the of reaction . This is done by either increasing or decreasing activation energy of molecule as catalyst are mainly of two types, `+ve` catalyst and -ve catalyst. |
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| 1839. |
Assertion (A) : If the activation energy of a reaction is zero, temperature will have no effect on the rate constant. Reason (R ): Lower the activation energy, faster is the reaction.A. If both assertion and reason are true and the reason is the correct explanation of the assertion.B. If both assertion and reason are true but the reason is not the correct explanation of the assertion.C. If assertion is true but reason is false.D. If assertion is false but reason is true. |
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Answer» Correct Answer - B According to Arrhenius equation, `k = Ae^(-E_(a)//RT)` when `E_(a) = 0`, `K = A` |
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| 1840. |
Assertion (A) : The order of a reaction can be fractional but molecularity is never fractional. Reason (R ): The order of reaction does not depend upon the stoichiometric coefficients of a balanced equation.A. If both `(A)` and `(R )` are correct, and `(R )` is the correct explnation of `(A)`.B. If both `(A)` and `(R )` are correct, but `(R )` is noth the correct explanation of `(A)`.C. If `(A)` is correct, but `(R )` is incorrect.D. If `(A)` is incorrect, but `(R )` is correct. |
| Answer» Correct Answer - A | |
| 1841. |
Assertion (A) : `k=Ae^(-E_(a)//RT)`, the Arrhenius equation represents the dependence of rate constant with temperature. Reason (R ): Plot of `log.k` against `1//T` is linear and the activation energy can be calculated with this plot.A. If both `(A)` and `(R )` are correct, and `(R )` is the correct explnation of `(A)`.B. If both `(A)` and `(R )` are correct, but `(R )` is noth the correct explanation of `(A)`.C. If `(A)` is correct, but `(R )` is incorrect.D. If `(A)` is incorrect, but `(R )` is correct. |
| Answer» Correct Answer - A | |
| 1842. |
Statement: The Arrhenius equation explains the temperature dependence of rate of a chemical reaction. Explanation: Plots of `log K` versus `1//T` are linear and the energy of activation is obtained from such plots.A. (a) `S` is correct but `E` is wrongB. (b) `S` is wrong but `E` is correctC. (c ) Both `S` and `E` are correct and `E` is correct explanation of `S`D. (d) Both `S` and `E` are correct but `E` is not correct explanation of `S`. |
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Answer» Correct Answer - C Explanation is correct reason for statement. |
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| 1843. |
The temperature dependence of the rate of a chemical reaction can be explained by Arrhenius equaiton which isA. `k = Ae^(Ea//RT)`B. `k = Ae^(-Ea//RT)`C. `k = Ae xx (E_(a))/(RT)`D. `k = Ae xx (RT)/(E_(a))` |
| Answer» Correct Answer - B | |
| 1844. |
The potential energy diagram for a reaction `X to Y` is given. A and C in the graph corresponding to A. A `to` activation energy, C `to Delta H^(@)`B. A `to` energy of reactants, C `to` energy of productsC. A `to Delta H^(@), C to` activation energyD. A `to` activation energy, C `to` threshold energy |
| Answer» Correct Answer - A | |
| 1845. |
Two plots are shown below between concentration and time t. Which of the given orders are shown by the graphs respectively? A. Zero order and first orderB. first order and second orderC. zero order and second orderD. frist order and first order |
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Answer» Correct Answer - C Linear plots are obtained in the graph of (A - x) vs t for zero order reaction and `(1)/(a -x)` vs t for second reaction |
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| 1846. |
The energy diagram of a reaction `P + Q to R + S` is given. What are A and B in the graphs? A. A `to` activation energy, B `to` heat of reactionB. A `to` threshold energy, B `to` heat of reactionC. A `to` heat of reaction, B `to` activation energyD. A `to` potential energy, B `to` energy of reaction |
| Answer» Correct Answer - A | |
| 1847. |
Observe the given graphs carefully. Which of the given orders are shown by the graphs respectively?A. zero order, First orderB. First order, Zero orderC. First order, first orderD. Second order, Zero order |
| Answer» Correct Answer - C | |
| 1848. |
Consider the reaction : `2H_(2)(g)+2NO(g)rarrN_(2)(g)+2H_(2)(g)` The rate law for this reaction is : Rate = `k[H_(2)][NO]^(2)` Under what conditions could these steps represent mechanism? `{:("Step 1:",2NO(g)hArrN_(2)O_(2)(g)),("Step 2:",N_(2)O_(2)+H_(2)rarrN_(2)O+H_(2)O),("Step 3:",N_(2)O+H_(2)rarrH_(2)O+N_(2)):}`A. These steps cannot be he mechanism under any circumstacesB. These steps could be the mechanism if step 1 is the slow stepC. These steps could be the mechanism if step 2 is the slow stepD. These steps could be the mechanism if step 3 is the slow step |
| Answer» Correct Answer - C | |
| 1849. |
Which of the following graphs is correct for second order reaction ?A. B. C. D. |
| Answer» Correct Answer - C | |
| 1850. |
Consider the reaction : `2H_(2)(g)+2NO(g)rarrN_(2)(g)+2H_(2)(g)` The rate law for this reaction is : Rate = `k[H_(2)][NO]^(2)` Under what conditions could these steps represent mechanism? `{:("Step 1:",2NO(g)hArrN_(2)O_(2)(g)),("Step 2:",N_(2)O_(2)+H_(2)rarrN_(2)O+H_(2)O),("Step 3:",N_(2)O+H_(2)rarrH_(2)O+N_(2)):}`A. These steps can never satisfy the rate lawB. Step 1 should be the slowest stepC. Step 2 should be the slowest stepD. Step 3 should be the slowest step |
| Answer» Correct Answer - C | |