Chemical Kinetics PYQs - Last 5 Years

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Practice 51 COMEDK Chemistry questions from Chemical Kinetics. Use the year-wise and type-wise breakdown to prioritize recent PYQs, then continue into the question list below.

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Last 5 Years Chemical Kinetics Questions

Showing 50 of 51 filtered questions.

1Chemical Kinetics

When the initial concentration of a zero order reaction is doubled, the half-life of the reaction is:

2Chemical Kinetics

Identify the correct values to be plotted in the graph, the slope of which can be used to determine the activation energy of a reaction.

3Chemical Kinetics

$60 \%$ of a first order reaction was completed in 60 min , then $50 \%$ of the same reaction can be completed in: $[\log 4=0.60, \log 5=0.69]$

4Chemical Kinetics

Rate law can be determined from a balanced chemical equation if

5Chemical Kinetics

The rate constants for two different reactions, $\mathrm{k}_1$ and $\mathrm{k}_2$ are $10^{16} \cdot \mathrm{e}^{-2000 / \mathrm{T}}$ and $10^{15} \cdot \mathrm{e}^{-1000 / \mathrm{T}}$ respectively. The temperature at which $k_1=k_2$ is

6Chemical Kinetics

In the synthesis of $\mathrm{NH}_3$ from $\mathrm{H}_2$ and $\mathrm{N}_2$, if $6 \times 10^{-2}$ mole of hydrogen disappears in 10 minutes, the number of moles of $\mathrm{NH}_3$ formed in 0.3 minutes is:

7Chemical Kinetics

\(\text { When the concentration of the reactant in a given reaction is halved and if the rate of reaction is halved, the order of the reaction is: }\)

8Chemical Kinetics

Which of the following factors is altered by the addition of a catalyst during a chemical reaction?

9Chemical Kinetics

The initial pressure of the system before decomposition for a first order gas phase reaction $A_{(g)} \rightarrow B_{(g)}+C_{(g)}$ was $\mathrm{P}_{\mathrm{i}}$. After lapse of time ' t ', total pressure of the system increased by ' x ' uni...

10Chemical Kinetics

A first order reaction is $50 \%$ complete in 30 minutes at 300 K and in 10 minutes at 320 K . The activation energy of the reaction ( $E_a$ ) is: $\left[R=8.314 \mathrm{~J} \mathrm{~K}^{-1} \mathrm{~mol}^{-1} ; \log 2=0.3010 ; \log 3=0.477...

11Chemical Kinetics

For a given reaction of the type $\frac{3}{5} X(a q) \rightarrow \frac{1}{2} Y(a q)+Z(g)$, the correct expression for the rate of disappearance of $X$ with reference to $Y$ is ___________

12Chemical Kinetics

$\mathrm{X} \rightarrow 2 \mathrm{Y}$ is a first order reaction where $1.0 \mathrm{~mol} / \mathrm{L}$ of the reactant yields $0.4 \mathrm{~mol} / \mathrm{L}$ of Y in 200 minutes. Calculate the half-life period of the reaction in minutes.

13Chemical Kinetics

Two chemical reactions of the same order have equal Frequency factor value. Their Activation energies differ by $26.8 \mathrm{~kJ} / \mathrm{mol}$. At 300 K if $k_2=x k_1$ find the value of $x$.

14Chemical Kinetics

Two statements, One Assertion (A) and the other Reason (R) are given. Choose the right option.
Assertion: The rate constant $(\mathrm{k})$ for a chemical reaction gets nearly doubled for a $10^0$ rise in temperature.
Reason: The number of b...

15Chemical Kinetics

The following results were obtained during study of the reaction $2 \mathrm{NO}(\mathrm{g})+\mathrm{Cl}_2(\mathrm{~g}) \rightarrow 2 \mathrm{NOCl}(\mathrm{g})$. Determine the value of $[\mathrm{X}]$ in $\mathrm{mol} / \mathrm{L}$

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16Chemical Kinetics

The order of a reaction $\mathrm{W}+\mathrm{X} ---- \rightarrow \mathrm{Y}+\mathrm{Z}$ with respect to W is 3 and with respect to X is 1. If the concentrations of both W and X are tripled, the rate of reaction will increase by _________ tim...

17Chemical Kinetics

When the temperature of a reaction $\mathrm{A}+\mathrm{B} \rightarrow \mathrm{C}$ is increased from 300 K to 310 K the rate constant increases by $12 \%$. What is the Activation energy of the reaction?

18Chemical Kinetics

During a chemical reaction $\mathrm{X} \rightarrow \mathrm{Y}$, the rates of reaction starting with initial concentrations of X as $4.0 \times 10^{-3} \mathrm{M}$ and $2.0 \times 10^{-3} \mathrm{M}$ are $4.8 \times 10^{-4} \mathrm{~mol} \ma...

19Chemical Kinetics

Choose the correct statement.

20Chemical Kinetics

The decomposition of $\mathrm{PH}_3$ follows first order kinetics. The time required for $3 / 4^{\text {th }}$ of $\mathrm{PH}_3$ to decompose is 75.76 s . Calculate the fraction of original amount of $\mathrm{PH}_3$ which will remain after...

21Chemical Kinetics

(i) and (ii) are 2 chemical reactions carried out at TK.
(i). $\mathrm{X} \rightarrow \mathrm{Y}+\mathrm{W}$ with $\mathrm{k}_1$ as rate constant.
(ii). $\mathrm{X} \rightarrow \mathrm{Z}+\mathrm{W}$ with $k_2$ as rate constant.
The Activat...

22Chemical Kinetics

The hydrogenation of Ethyne is carried out at 600 K . The same reaction when carried out in presence of a catalyst maintaining the same rate constant, the temperature required is only 400 K . If the catalyst lowers the Activation energy of ...

23Chemical Kinetics

The time needed for completion of $80 \%$ is $y$ times the half-life period of a first order reaction. What is the value of $y$ ?

24Chemical Kinetics

Which one of the following is incorrect?

25Chemical Kinetics

The rate constant for a zero order reaction $\mathrm{A} \rightarrow \mathrm{B}+\mathrm{C}$ is $6.0 \times 10^{-3} \mathrm{molL}^{-1} \mathrm{~s}^{-1}$.
What would be the time taken for the initial concentration of A to decrease from 0.2 M t...

26Chemical Kinetics

Given below are 4 graphs [A], [B], [C] and [D]

Identify the 2 graphs that represent a Zero order reaction?

27Chemical Kinetics

The rate constant for the reaction \(\mathrm{A} \rightarrow \mathrm{B}+\mathrm{C}\) at \(500 \mathrm{~K}\) is given as \(0.004 \mathrm{~s}^{-1}\). At what temperature will the rate constant become \(0.014 \mathrm{~s}^{-1}\) ? $$\mathrm{E}_{...

28Chemical Kinetics

A given chemical reaction is represented by the following stoichiometric equation.
\(3 X+2 Y+\frac{5}{2} Z \rightarrow P_1+P_2+P_3\)
The rate of reaction can be expressed as _________.

29Chemical Kinetics

For the reaction \(\mathrm{Cl}_{2(\mathrm{~g})}+2 \mathrm{NO}_{(\mathrm{g})} \rightarrow 2 \mathrm{NOCl}_{(\mathrm{g})}\), the following data was obtained:

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30Chemical Kinetics

The time required for \(80 \%\) of a first order reaction is "\(y\)" times the half-life period of the same reaction. What is the value of "\(y\)"?

31Chemical Kinetics

In the presence of a catalyst at a given temperature of \(27^{\circ} \mathrm{C}\), the Activation energy of a specific reaction is reduced by \(100 \mathrm{~J} / \mathrm{mol}\). What is the ratio between the rate constants for the catalysed...

32Chemical Kinetics

For a reaction \(5 X+Y \rightarrow 3 Z\), the rate of formation of \(Z\) is \(2.4 \times 10^{-5} \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}\) Calculate the average rate of disappearance of \(\mathrm{X}\).

33Chemical Kinetics

The Activation energy for the reaction \(A \rightarrow B+C\), at a temperature \(\mathrm{TK}\) was \(0.04606 \mathrm{~RT} \mathrm{~J} / \mathrm{mol}\). What is the ratio of Arrhenius factor to the Rate constant for this reaction?

34Chemical Kinetics

The following data was recorded for the decomposition of XY compound at 750K

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35Chemical Kinetics

For a given reaction, ,\(\mathrm{X}(\mathrm{g})+\mathrm{Y}(\mathrm{g} \rightarrow \mathrm{Z}(\mathrm{g})\), the order of reaction with respect to \(\mathrm{X}\) and \(\mathrm{Y}\) are \(\mathrm{m}\) and \(\mathrm{n}\) respectively. If the c...

36Chemical Kinetics

The half-life for a zero order reaction is

37Chemical Kinetics

The rate of appearance of bromine is related to the disappearance of bromide ion in the equation given below is:
$$\mathrm{BrO}_3^{-} \text {(aq) }+5 \mathrm{Br}^{-} \text {(aq) }+6 \mathrm{H}^{+} \rightarrow 3 \mathrm{Br}_2(\mathrm{l})+3 \...

38Chemical Kinetics

For the reaction, \(\mathrm{A}+3 \mathrm{~B} \rightarrow 2 \mathrm{C}+\mathrm{D}\), the concentration of \(\mathrm{A}\) changes from 0.0150 to 0.0125 in 1 minute. The rate of formation of \(\mathrm{C}\) in $$\mathrm{mol} \mathrm{~L}^{-1} \m...

39Chemical Kinetics

The temperature \((\mathrm{T})\) and rate constant \((\mathrm{k})\) for a first order reaction \(\mathrm{R} \rightarrow \mathrm{P}\), was found to follow the equation \(\log \mathrm{k}=-(2000) \frac{1}{\mathrm{~T}}+8.0\). The pre-exponentia...

40Chemical Kinetics

Given below a first order reaction in the gas phase
\(\mathrm{A}(\mathrm{g}) \rightarrow \mathrm{B}(\mathrm{g})+\mathrm{C}(\mathrm{g})\)
If the initial pressure of the system is \(\mathrm{P}_{\mathrm{i}}\) and the total pressure at $$\mathr...

41Chemical Kinetics

Given below are graphs showing the variation in velocity constant with temperature on Kelvin scale. Identify the graph which represents Arrhenius equation.

42Chemical Kinetics

Match the details given in Column I with those given in Column II

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43Chemical Kinetics

The rate constant for a First order reaction at \(560 \mathrm{~K}\) is \(1.5 \times 10^{-6}\) per second. If the reaction is allowed to take place for 20 hours, what percentage of the initial concentration would have converted to products?

44Chemical Kinetics

For a reaction of the type, \(2 \mathrm{X}+\mathrm{Y} \rightarrow \mathrm{A}+\mathrm{B}\), the following is the data collected:

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45Chemical Kinetics

A first order reaction proceeds to \(90 \%\) completion. What will be the approximate time taken for \(90 \%\) completion in relation to \(t_{1 / 2}\) of the reaction?

46Chemical Kinetics

For a reaction, \(2 A+B \longrightarrow\) products,
If concentration of \(B\) is kept constant and concentration of \(A\) is doubled then rate of reaction is

47Chemical Kinetics

At \(300 \mathrm{~K}\), the half-life period of a gaseous reaction at an initial pressure of \(40 \mathrm{~kPa}\) is 350 s. When pressure is \(20 \mathrm{~kPa}\), the half-life period is 175 s. What is the order of the reaction?

48Chemical Kinetics

How much faster would a reaction proceed at \(25^{\circ} \mathrm{C}\) than at \(0^{\circ} \mathrm{C}\) if the activation energy is \(65 \mathrm{~kJ}\)?

49Chemical Kinetics

For the reaction 2N\(_2\)O\(_5\) \(\to\) 4NO\(_2\) + O\(_2\).
If initial pressure is 100 atm and rate constant \(k\) is 3.38 \(\times\) 10\(^{-5}\) s\(^{-1}\). after 20 min the final pressure of N\(_2\)O\(_5\) will be

50Chemical Kinetics

Which of the following statement is incorrect about activation energy?