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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 |
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Answer» 8.73 min 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. |
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| 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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Answer» `44.1" s"` `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` |
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| 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 |
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Answer» 24.1 s |
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| 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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Answer» 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 |
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| 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 |
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Answer» 24.1 s `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 |
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| 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 …… |
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Answer» 34.1 `t_((1)/(2))=(2.303xx0.3010xx10)/(2.303xx0.124)=24.27` second |
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| 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 |
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Answer» `34.1s` 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` |
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| 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. |
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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.` |
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| 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)) : |
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Answer» 7.0 MOL `L^(-1)` `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 %` |
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| 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 : |
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Answer» 24 times Alternatively, as rate of reaction is doubled for EVERY `10^(@)` rise in temperature, increase in reaction rate `=2^(5)=32` times. |
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| 24711. |
The rate of a chemical reaction is increased in presence of a catalyst. This is because |
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Answer» activation ENERGY of the REACTION is less in the new path |
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| 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, |
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Answer» 10 times |
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| 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 |
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Answer» 20 times |
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| 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: |
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Answer» 29 times |
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| 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: |
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Answer» 29 times |
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| 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 : |
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Answer» 32 times |
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| 24717. |
The rate of a chemical reaction doubles for an increases of 10 K in absolute temperature from 298 K. Calculate E_e. |
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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)` |
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| 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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Answer» The reactant concentration remain CONSTANT as the reaction proceeds. |
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| 24720. |
The rate of a chemical reaction….. |
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Answer» INCREASES as the REACTION proceeds. |
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| 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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Answer» 2 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` |
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| 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 |
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Answer» k |
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| 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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Answer» 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. |
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| 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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Answer» Is zero |
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| 24725. |
The rate law of the reaction RCl+NaOHtoROH+NaCl is given by Rate =k[RCI]. The rate of this reaction |
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Answer» A & B |
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| 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? |
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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)` |
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| 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» 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, |
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Answer» Zero |
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| 24730. |
The rate law of nitration of benzene using a mixture of nitric acid and sulphuric acid is |
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Answer» RATE `=k ["BENZENE"] [NO_(2)^(+)] [H^(+)]` |
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| 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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Answer» 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)` |
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| 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 |
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Answer» (m + N) |
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| 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 ? |
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Answer» |
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| 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 : |
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Answer» Solution :(B) Let rate = `k [A]^(2) [B] =x ` rate `= k [2A]^(2) [2B] = 8 b[A]^(2) [B] =8x ` |
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| 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 |
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Answer» unaffected by increasing temperature of the reaction `R_(2) = k[0.5 RCl]^(1)[NaOH]` `:. R_(2) = 0.5 R_(1)` |
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| 24736. |
The rate law for the reactionSucrose + Water overset([H^(+)])to Glucose + Fructose is given by : |
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Answer» Rate = K [sucrose] [water] |
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| 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» 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 |
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Answer» RATE=K[A].[B] |
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| 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 - |
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Answer» rate does not depend on the concentration of acid |
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| 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 |
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Answer» DOUBLED on doubling the concentration of sodium hydroxide |
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| 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 ? |
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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. |
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| 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. |
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Answer» 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)` |
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| 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 |
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Answer» 10 |
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| 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 |
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Answer» `(m+n)` |
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| 24749. |
The rate law for the chemical reaction : 2NO_(2)Clrarr 2NO_(2)+Cl_(2) is :The rate determining step is : |
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Answer» `2NO_(2)Cl RARR 2NO_(2)+2CL` |
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| 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 . |
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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 . |
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