Order of Reaction

Q.

The rate constant for a first order reaction is 60 s⁻¹. How much time will it take to reduce the initial concentration of the reactant to its 1/16^th value?

Q.

What is the difference between the rate of reaction and the reaction rate constant?

Q.

How can you balance an equation with the hit and trial method? Explain with an example.

Q. If the initial concentration of the reactant is doubled, the time for half reaction is also doubled. Then the order of the reaction is

1. 
   Zero
2. 
   One
3. 
   Fraction
4. 
   None

Q. The decomposition of azo methane, at a certain temperature according to the equation
$(C{H}_3{)}_2{N}_2\to C_2{H}_6+N_2$ is a first order reaction.
After $40$ minutes from the start, the total pressure developed is found to be $350$ mm Hg in place of initial pressure $200$ mm Hg of azo methane. the value of rate constant $k$ is:

1. $2.88\times {10}^{-4}{s}^{-1}$
2. $1.25\times {10}^{-4}{s}^{-1}$
3. $5.77\times {10}^{-4}{s}^{-1}$
4. $3.52\times {10}^{-4}{s}^{-1}$

Q.

What is the equivalent weight of ${\mathrm{H}}_2{\mathrm{O}}_2$ in decomposition reaction?

Q.

Is rate constant dependent on the concentration?

Q. Rate of reaction, $A+2B\to \text{Product}$ is$R=k{\left[B\right]}^2\left[A\right]$. If B is taken in large excess then the order of reaction is

1. Pseudo second order
2. Pseudo first order
3. First order
4. Second order

Q. The equilibrium constant for the reaction,
$N_2+2O_2\rightleftharpoons 2N{O}_2$ is $100$. The equilibrium constant for the reactions:
(a) $2N{O}_2\rightleftharpoons N_2+2O_2$ is $K_1$
(b) $N{O}_2\rightleftharpoons \frac{1}{2}{N}_2+O_2$ is $K_2$
Find the value of $K_1\times K_2$.

1. $0.1$
2. $0.01$
3. $0.001$
4. $1$

Q.

The reaction of ozone with oxygen atoms in the presence of chlorine atoms can occur by a two step process shown below :
$O_3$(g) + Cl•(g) → $O_2$(g) + ClO•(g) ____ (i)
$k_i=5.2\times {10}^{9}L{mol}^{-1}{s}^{-1}$
ClO•(g) + O•(g) → $O_2$(g) + Cl•(g) ____ (ii)
$k_{ii}=2.6\times {10}^{10}L{mol}^{-1}{s}^{-1}$
The closest rate constant for the overall reaction $O_3$(g) + O•(g) → 2$O_2$(g) is :

Q.

Which of the following statements is not correct about order of a reaction ?
(a) The order of a reaction can be fractional number
(b) Order of a reaction is experimentally determined quantity
(c) The order of reaction is always equal to the sum of the stoichiometric coefficients of reactants in the balanced chemical equation for a reaction
(d) The order of a reaction is the sum of the powers of molar concentration of the reactants in the rate law expression.

Q.

The decomposition of dimethyl ether leads to the formation of $C{H}_4$, $H_2$ and $CO$ and the reaction rate is given by:

Rate $=k[C{H}_{3}OC{H}_3{]}^{\frac{3}{2}}$. The rate of reaction is followed by increase in pressure in a closed vessel, so the rate can be expressed in terms of the partial pressure of dimethyl ether i.e. Rate = $k(p_{C{H}_{3}OC{H}_3}{)}^{\frac{3}{2}}$. If the pressure is measured in bar and time in minutes, then what are the units of rate and rate constants?

Q. For the reaction A+B→ products, it is observed that a)on doubling the initial concentration of A only the rate of the reaction is doubled and b)on doubling the initial concentrations of both A and B there is a change by a factor of 8 in the rate of the reaction The rate of this reaction is given by,

Q. A bacterial infection in an internal wound grows as $N^{\prime }\left(t\right)=N_{0}exp\left(t\right)$, where the time $t$ is in hours. A dose of antibiotic, taken orally, needs 1 hour to reach the wound. Once it reaches there, the bacterial population goes down as $\frac{dN}{dt}=-5N^2$. What will be the plot of $\frac{N_0}{N}vst$ after $1hour$?

1. 
2. 
3. 
4. 

Q.

Match List-I with List-II-Wirtz reaction, Sandmeyer reaction, Fitting reaction, Gattermann reaction

choose the correct answer from the answer given below:

1. (a)-(ii), (b)-(i), (c)-(iv), (d)-(iii)

2. (a)-(iii), (b)-(iv), (c)-(i), (d)-(ii)

3. (a)-(ii), (b)-(iv), (c)-(i), (d)-(iii)

4. (a)-(iii), (b)-(i), (c)-(iv), (d)-(ii)

Q. The rate constant, the activation energy and the frequency factor of a chemical reaction at ${25}^{\circ }C$ are $3.0\times {10}^{-4}{\text{s}}^{-1},104.4{\text{kJ mol}}^{-1}$ and $6.0\times {10}^{14}{\text{s}}^{-1}$ respectively. The value of the rate constant as $T\to \infty$ is:

1. $2.0\times {10}^{18}{\text{s}}^{-1}$
2. $6.0\times {10}^{14}{\text{s}}^{-1}$
3. Infinite
4. $3.6\times {10}^{30}{\text{s}}^{-1}$

Q. For the reaction 2A + 3B $\to$products, A is in excess and on changing the concentration of B from 0.1 M to 0.4 M, rate becomes doubled. Thus, rate law is

1. $\frac{dx}{dt}=k\left[A{]}^2\right[B{]}^2$
2. $\frac{dx}{dt}=k\left[A\right]\left[B\right]$
3. $\frac{dx}{dt}=k\left[A\right]0[B{]}^2$
4. $\frac{dx}{dt}=k[B{]}^{1/2}$

Q.

Assertion (A) Order of the reaction can be zero or fractional.

Reason (R) We cannot determine order from balanced chemical equation.

(a) Both assertion and reason are correct and the reason is correct explanation of assertion
(b) Both assertion and reason are correct, but reason does not explain assertion.
(c) Assertion is correct, but reason is incorrect
(d) Both assertion and reason are incorrect
(e) Assertion is incorrect but reason is correct.

Q. 40% of HI undergoes decomposition to $H_2$ and $I_2$ at $300K$. $\Delta G^{\circ }$ for this decomposition reaction at one atmosphere pressure is ______ $Jmo{l}^{–1}$. [nearest integer]
($\text{Use}R=8.31J{K}^{–1}mo{l}^{–1};log2=0.3010,ln10=2.3,log3=0.477)$

Q. The decomposition of dimethyl ether is a fractional order reaction. The rate of reaction is given by
$Rate=k(P_{C{H}_{3}OC{H}_3}{)}^{3/2}$. If the pressure is measured in bar and time in minutes, then what are the units of rate and rate constant respectively?

1. $barmi{n}^{-1},ba{r}^{2}mi{n}^{-1}$
2. $barmi{n}^{-1},ba{r}^{\frac{-1}{2}}mi{n}^{-1}$
3. $ba{r}^{\frac{-1}{2}}mi{n}^{-1},ba{r}^{2}mi{n}^{-1}$
4. $barmi{n}^{-1},ba{r}^{\frac{1}{2}}mi{n}^{-1}$

Q. Describe one method to determine rate law and order of a reaction.

Q. $Me-C\equiv C-Me\underset{EtOH,-{33}^{\circ }C}{\overset{Na/N{H}_3(liq.)}{\to }}\underset{=}{X}\stackrel{dil.alkalineKMn{O}_4}{\to }$ Product(s)
The product(s) from the above reaction will be

1. 
2. 
3. 
4. 

Q. The gas phase thermal decomposition of one mole of di-tert-butyl peroxide, in a constant volume apparatus, yields two moles of acetone and one mole of ethane. If the reaction obeys first order kinetics, the correct expression for the rate constant as a function of time $\left(t\right)$, initial pressure $\left(p_i\right)$ and total pressure $\left(p\right)$.

1. $\frac{1}{t}\ln \frac{p_i}{(3p_i-p)}$
2. $\frac{1}{t}\ln \frac{2p_i}{(3p_i-p)}$
3. $\frac{1}{t}\ln \frac{2p_i}{(3p_i-2p)}$
4. $\frac{1}{t}\ln \frac{p_i}{(3p_i-2p)}$

Q. The rate law expression for four reactions are give below. In which case, the percentage increase in the rate of reaction would be maximum when the concentration of A is doubled?

1. $r=k[A{]}^{\frac{3}{2}}$
   
   
2. $r=k\left[A\right]$
3. $r=k[A{]}^{\circ }$
4. $r=k[A{]}^2$

Q.

Why can we not determine the order of a reaction by taking into consideration the balanced chemical equation?

Q. The unit of rate constant for a zero order reaction is:

1. $s^{-1}$
2. $mol{L}^{-1}{s}^{-1}$
3. $Lmo{l}^{-1}{s}^{-1}$
4. $L^{2}mo{l}^{-2}{s}^{-1}$

Q. A flask of capacity 1 L contains $N{H}_3$ at 1 atm and ${25}^{\circ }\text{C}$. A spark is passed through until all the $N{H}_3$ is decomposed to $N_2$ and $H_2$. Calculate the pressure (in atm) of gases left at ${25}^{\circ }\text{C}$
after the reaction.

Q.

(a) What would you observe if hydrogen gas is passed over heated copper (II) oxide?

(b) Which property of hydrogen is illustrated in (a)

(c) Give a balanced equation for the reaction taking place in (a)

(d) Mention one large scale use of the property named in (b)

Q. Rate constant of a reaction is $175litr{e}^{2}mo{l}^{-2}se{c}^{-1}$. What is the order of reaction?

Q.

If I is the intensity of absorbed light and C is the concentration of AB for the photochemical process $AB+hV\to AB$,
then the rate of formation of AB is directly proportional to?

1. C.I

2. C

3. I

4. $I^2$