Rate Constant

Q. Draw the energy profile diagram of SN1 reaction.

Q.

Calculate the work done by the system in an irreversible (single step) adiabatic expansion of 2 mole of a polyatomic gas $(\gamma -\frac{4}{3})$ from 300K and pressure 10 atm to 1 atm:

1. - 890 Cal mole^-1 K^-1

2. - 227 R

3. - 405 R

4. - 53.67 kJ mole^-1 K^-1

Q.

The quantity k in a rate law expression

1. is independent of concentration

2. is called the Arrhenius constant

3. is dimensionless

4. is independent of the temperature

Q. What Is The SI Unit Of Molarity, Molality And Normality?What Is The Relation Between These Three Concentration Units?

Q. 32. How to calculate n factor in a given reaction?

Q. .Equilibrium concentrations of A and B involved infollowing equilibrium are 0.01 M and 0.02 Mrespectively: A(g) B(g)If 0.01 M of A is added at equilibrium, thenat new equilibrium concentration of B will be(2) 2.67 x 10-2 M(1) 6.67 x 10-2 M(4) 1.33 x 10-1 M(3) 1.33 10-2 M

Q. For the non-stoichiometric reaction 2A + B ⟶ C + D. The following kinetic data were obtained in three separate experiments, all at 298 K.

Initial concentration (A)	Initial concentration (B)	Initial rate of formation of C $\left(mol{L}^1{S}^{-1}\right)$
0.1M	0.1M	$1.2\times {10}^{-3}$
0.1M	0.2M	$1.2\times {10}^{-3}$
0.2M	0.1M	$2.4\times {10}^{-3}$

The rate law for the formation of C is :
(IIT-JEE-2014)

1. $\frac{dc}{dt}=k\left[A\right][B{]}^2$

2. $\frac{dc}{dt}=k\left[A\right]$

3. $\frac{dc}{dt}=k\left[A\right]\left[B\right]$
4. $\frac{dc}{dt}=k\left[A{]}^2\right[B]$

Q.

Mr. Samwell Tarly has to learn Chemistry to become a Maester. He is stuck with Kinetics. Will you help him?

(Maester is just Master in their language)

Choose the appropriate definition of rate constant.

1. The constant which relates rate of reaction to the temperature.
2. The rate of the reaction when concentration of reactants is equal to one.
3. The concentration when rate of reaction is equal to $1mol{L}^{-1}se{c}^{-1}$
4. The constant which is added to the rate equation to make everything equal to one.

Q. For the reaction $3A\left(g\right)\stackrel{k}{\to }B\left(g\right)+C\left(g\right)$, k is ${10}^{-4}Lmo{l}^{-1}mi{n}^{-1}$. If [A] = 0.5 M then the value of $\frac{-d\left[A\right]}{\mathrm{dt}}$ (in $M{s}^{-1}$) is

1. $7.5\times {10}^{-5}$
2. $3\times {10}^{-4}$
3. $2.5\times {10}^{-5}$
4. $1.25\times {10}^{-6}$

Q.

A reaction in which all reactants are in the same phase is called

1. elementary

2. bimolecular

3. homogeneous

4. heterogeneous

Q.

A reaction : $A_2+B\to$ Products, involves the following mechanism :
$A_2\rightleftharpoons 2A\left(fast\right)$ (A being the intermediate)
$A+B\underset{k_2}{\to }\left(slow\right)$.The rate law consistent to this mechanism is :

1. $rate=k\left[A_2\right]\left[B\right]$

2. $rate=k\left[A_2{]}^2\right[B]$

3. $rate=k\left[A_2{]}^{\frac{1}{2}}\right[B]$

4. $rate=k\left[A_2\right][B{]}^2$

Q. For the reaction $3A\left(g\right)\stackrel{k}{\to }B\left(g\right)+C\left(g\right)$, k is ${10}^{-4}Lmo{l}^{-1}mi{n}^{-1}$. If [A] = 0.5 M then the value of $\frac{-d\left[A\right]}{\mathrm{dt}}$ (in $M{s}^{-1}$) is

1. $7.5\times {10}^{-5}$
2. $3\times {10}^{-4}$
3. $2.5\times {10}^{-5}$
4. $1.25\times {10}^{-6}$

Q.

A reaction : $A_2+B\to$ Products, involves the following mechanism :
$A_2\rightleftharpoons 2A\left(fast\right)$ (A being the intermediate)
$A+B\underset{k_2}{\to }\left(slow\right)$.The rate law consistent to this mechanism is :

1. $rate=k\left[A_2\right]\left[B\right]$

2. $rate=k\left[A_2{]}^2\right[B]$

3. $rate=k\left[A_2{]}^{\frac{1}{2}}\right[B]$

4. $rate=k\left[A_2\right][B{]}^2$

Q. A + B → C, the unit of rate constant is
(1) S^–1 (2) S^–1 mol L^–1 (3) S^–1 mol^–1 L S

Q. The rate constant of the reaction $A\to B$ is $0.6\times {10}^{-3}{\text{mol L}}^{-1}{\text{s}}^{-1}$. If the concentration of $A$ is $5M$, then concentration of $B$ after $20$ minutes is:

Q. The decomposition of hydrogen peroxide in an aqueous solution is a reaction of first order. It can be followed by titrating 10 mL portions of reaction mixture at various times from the beginning of reaction against a standard solution of $KMn{O}_4$. Volume of $KMn{O}_4$ solution used in each case is proportional to the remaining concentration of $H_2{O}_2$. From the following data, calculate the rate constant of the reaction.
$\begin{array}{cccc}\text{Time (in seconds)}& 0& 600& 1200\\ KMn{O}_4\text{sol. used (in mL)}& 22.8& 13.8& 8.20\end{array}$

1. $k=8.44\times {10}^{-4}{\text{sec}}^{-1}$
2. $k=8.44\times {10}^{-2}{\text{sec}}^{-1}$
3. $k=2.44\times {10}^{-6}{\text{sec}}^{-1}$
4. $k=2.22\times {10}^{-4}{\text{sec}}^{-1}$

Q.

The following data pertains to reaction between A and B :
$\begin{array}{cccc}S.NO.& \left[A\right]mol{L}^{-1}& mol{L}^{-1}& Rate\left(mol{L}^{-1}tim{e}^{-1}\right)\\ 1& 1.0\times {10}^{-2}& 2.0\times {10}^{-2}& 2.0\times {10}^4\\ 2& 2.0\times {10}^{-2}& 2.0\times {10}^{-2}& 4.0\times {10}^{-4}\\ 3& 2.0\times {10}^{-2}& 4.0\times {10}^{-2}& 8.0\times {10}^{-4}\end{array}$
Which of the following inference(s) can be drawn from the above data ?

1. Rate constant of the reaction is $1.0\times {10}^{-4}$

2. Rate law of the reaction is: rate $=k\left[A\right]\left[B\right]$

3. Rate of reaction increases four times on doubting the concentration of both the reactants.

Select the correct answer using the codes given below:

1. 1, 2 and 3

2. 1 and 2

3. 2 and 3

4. 3 only

Q.

For the reaction : $aA+bB\to$ Products, the rate law is given by Rate = $k\left[A{]}^m\right[B{]}^n$. On making the concentration of A two-fold and halving that of B, the ratio of the new rate to the earlier rate of the reaction would be:

1. $n-1$

2. $m+n$

3. $2^{-(m+n)}$

4. $2^{(m-n)}$