Rate Constant

Q.

The rate of a first order reaction is 0.04mol/L/s at10minutes and 0.03mol/L/s at 20minutes after initiation. Find the half life of the reaction.

Q. If the rate constant for a first order reaction is k, the time (t) required for the completion of 99% of the reaction is given by:

1. t = 0.693/k
   
2. t = 6.909/k
   
3. t = 4.606/k
   
4. t = 2.303/k

Q.

How to calculate the dissociation constant?

Q.

What is the relation between half life and average life ?

Q.

The following results have been obtained during the kinetic studies of the reaction, $2A+B\to C+D$
$\begin{array}{cccc}Experiment& \left[A\right]mol{L}^{-1}& \left[B\right]mol{L}^{-1}& Initialrateofformationof\\ & & & D/mol{L}^{-1}min\\ I& 0.1& 0.1& 6.0\times {10}^{-3}\\ II& 0.3& 0.2& 7.2\times {10}^{-2}\\ III& 0.3& 0.4& 2.88\times {10}^{-1}\\ IV& 0.4& 0.1& 2.40\times {10}^{-2}\end{array}$
Determine the rate law and the rate constant for the reaction.

Q.

What is the effect of temperature on the rate constant of a reaction? How can this temperature effect on rate constant be represented quantitatively?

Q.

What is the formula to find the flocculation value?

Q. The following results were obtained during the kinetic studies of the reaction:$2A+B\to Products$

Experiment	[A] (in mol $L^{-1}$	[B] (in mol $L^{-1}$)	Initial rate of the reaction (in mol $L^{-1}mi{n}^{-1}$ )
(I)	0.10	0.20	6.93x${10}^{-3}$
(II)	0.10	0.25	6.93x${10}^{-3}$
(III)	0.20	0.30	1.386x${10}^{-2}$

The time (in minutes) required to consume half of A is:

1. 5
2. 100
3. 1
4. 10

Q.

1. 7.33
2. 733
3. 0.733
4. 73.3

Q. Which of the following polymer is a homopolymer?

1. Bakelite
2. Nylon-66
3. Terylene
4. Neoprene

Q. the temperature coefficient of a certain reaction is found to be 3 if temperature changes from 25^o to 55^o the new rate of the reaction will b

Q. In a first order reaction the concentration of reactant decreases from $800{\text{mol/dm}}^3$ to $50{\text{mol/dm}}^3$ in $2\times {10}^4\text{sec}$. The rate constant of the reaction in ${\text{sec}}^{-1}$ is:

1. $2\times {10}^4$
2. $3.45\times {10}^{-5}$
3. $2\times {10}^{-4}$
4. $1.386\times {10}^{-4}$

Q.

Molarity of 0.1 N of oxalic acid?

Q. The rate constant of a first-order reaction is ${10}^{–3}{\text{min}}^{–1}$ at $300\text{K}$. The temperature coefficient of the reaction is $2$. What is the rate constant of the reaction at $350\text{K}$ approximately?

1. $16\times {10}^{-3}$
2. $64\times {10}^{-3}$
3. $32\times {10}^{-3}$
4. $2^{50}$

Q.

R₁ and R₂ are two reactions having identical pre-exponential factors. The activation energy of R₁ exceeds R₂ by $10{\mathrm{kJmol}}^{-1}$.k₁ and k₂ are two rate constants for reaction R₁ and R₂ at$300\mathrm{K}$, then the ratio of $\frac{{\mathrm{k}}_2}{{\mathrm{k}}_1}$ will be?( R=$8.314{\mathrm{Jmol}}^{-1}{\mathrm{K}}^{-1}$)

1. $6$

2. $4$

3. $8$

4. $12$

Q.

Distinguish between specific reaction rate and rate of the reaction

Q.

The rate of a chemical reaction doubles for every $10°\mathrm{C}$ rise in temperature. If the temperature is raised by $50°\mathrm{C}$, The rate of the reaction increases by about?

Q.

For the decomposition of azoisopropane to hexane and nitrogen at 543 K, the following data are obtained. Calculate the rate constant.
$\begin{array}{cc}t\left(s\right)& p\left(mmofHg\right)\\ 0& 35.0\\ 360& 54.0\\ 720& 63.0\end{array}$

Q. Rate constant $k=2.303{\text{min}}^{-1}$ for a particular reaction. The initial concentration of the reaction is $1{\text{mol litre}}^{-1}$, then the rate of reaction after $1$ minute is:

1. $2.303{\text{Mmin}}^{-1}$
2. $0.2303{\text{Mmin}}^{-1}$
3. $0.1{\text{Mmin}}^{-1}$
4. None of these

Q. A first order reaction is 50% completed in 40 minutes at 300 K and in 20 minutes at 320 K. Calculate the activation energy of the reaction.

(Given : log 2 = 0.3010, log 4 = 0.6021, R = 8.314 $J{K}^{-1}mo{l}^{-1})$

Q.

${\mathbf{NaClO}}_{\mathbf{3}}$ is used, even in spacecrafts, to produce ${\mathbf{O}}_{\mathbf{2}}$. The daily consumption of pure ${\mathbf{O}}_{\mathbf{2}}$ by a person is 492 L at 1 atm, 300 K. How much amount of ${\mathbf{NaClO}}_{\mathbf{3}}$, in grams, is required to produce ${\mathbf{O}}_{\mathbf{2}}$ for the daily consumption of a person at 1 atm, 300 K?

$$\begin{gathered} {\mathrm{NaClO}}_3\left(\mathrm{s}\right)+\mathrm{Fe}\left(\mathrm{s}\right)\to {\mathrm{O}}_2\left(\mathrm{g}\right)+\mathrm{FeO}\left(\mathrm{s}\right)+\mathrm{NaCl}\left(\mathrm{s}\right) \\ \mathrm{R}=0.082\mathrm{L}\mathrm{atm}{\mathrm{mol}}^{–1}{\mathrm{K}}^{–1} \end{gathered}$$

Q. In the chemical reaction $A+B\to AB;B$ is acting as a limiting reagent then choose the correct option.

1. $\text{A = 50 atm, B = 100 atm}$
2. $\text{A = 100 atm, B = 200 atm}$
3. $\text{A = 50 atm, B = 30 atm}$
4. $\text{A = 50 atm, B = 200 atm}$

Q. If the rate constant of a reaction is $2.303\times {10}^{-4}{s}^{-1}$, then the time required to reduce 1.6 M of the reactant to 0.4 M is:
(log 2 = 0.3)

1. 50 min
2. 20 min
3. 150 min
4. 100 min

Q. Half-life period of a first-order reaction is $10$ minutes. Starting with $10$ ${\text{mol L}}^{-1}$, rate after $20$ minutes will be :

1. $0.0693\text{mole L}{\text{min}}^{-1}$
2. $0.0693\times 2.5{\text{mol L}}^{-1}{\text{min}}^{-1}$
3. $0.693\times 5{\text{mol L}}^{-1}{\text{min}}^{-1}$
4. $0.693\times 10{\text{mol L}}^{-1}{\text{min}}^{-1}$

Q. A gaseous reaction A(g) $\leftrightarrow$ 2B(g) + C(g) is found to be of first order. If the reaction is started with p_A = 90 mm Hg, the total pressure after 10 min is found to be 180 mm Hg. The rate constant of the reaction is

1. $4.60\times {10}^{-3}{s}^{-1}$
2. $4.90\times {10}^{-3}{s}^{-1}$
3. $1.15\times {10}^{-3}{s}^{-1}$
4. $6.9\times {10}^{-2}{s}^{-1}$

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

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

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

Q.

The rate constant $k_1$ of a reaction is found to be double that of rate constant $k_2$ of another reaction. The relationship between corresponding activation energies of the two reactions at the same temperature ($E_1$ and $E_2$) can be represented as:

Q. Rate constant of a first order reaction is $0.0693{\text{min}}^{-1}$. If we start with $20{\text{mol L}}^{-1}$, it is reduced to $2.5{\text{mol L}}^{-1}$ in:
(Given $\log 2=0.3010$)

1. $10\text{min}$
2. $20\text{min}$
3. $30\text{min}$
4. $40\text{min}$

Q. The rate of a first order reaction is $1.8\times {10}^{-3}mol{L}^{-1}mi{n}^{-1},$ when the initial concentration is 0.3 mol $L^{-1}$ . The rate constant in the units of second is

1. ${10}^{-4}{s}^{-1}$
2. $6\times {10}^{-2}{s}^{-1}$
3. ${10}^{-2}{s}^{-1}$
4. $6\times {10}^2{s}^{-1}$

Q. 1.If the rate of reaction increases to two times with every 10 degree rise in temperature then if we raise the temperature by 40 degree the new rate of the reaction will be