List of top Chemistry Questions

For a pseudo first order reaction, $CH_{3}COOC_{2}H_{5}+H_{2}O $ $ { <=>[H^{+}] }$ $CH_{3}COOH+C_{2}H_{5}OH$ the net rate is given by $\frac{d x}{d t}=4\times10^{-4} L mol^{-1} s^{-1} \left[\left(CH_{3}COOC_{2}H_{5}\right)\right]-3\times10^{4}L \, mol^{-1} s^{-1}\left[CH_{3}COOH\right]\left[C_{2}H_{5}OH\right]$ Then, the equilibrium constant of the reaction would be

For a second order reaction in which both the reactants have equal initial concentration, the time taken for 20% completion of reaction is 500 second. What will be the time taken for 60% of the reaction?

For the reaction $4A + B \to 2C + 2D,$ which of the following statements is not correct

From the above figure, the activation energy for the reverse reaction would be

Half life period of 2nd order reaction is

Half-life period of a first order reaction is $10$ min. What percentage of the reaction will be completed in $100$ min?

If initial concentration is doubled, the time for half reaction is also doubled, the order of reaction is

In acidic medium, the rate of reaction between $[BrO_{3}]$ and $[Br^{-}]$ ions is given by the expression $-\frac{d \left[BrO_{3}^{-}\right]}{d t}=k\left[BrO_{3}^{-}\right]\left[Br^{-}\right]\left[H^{+}\right]^{2}$ It means (i) rate constant of the reaction depends upon the concentration of $H^{+}$ ions (ii) rate of reaction is independent of the concentration of acid added (iii) the change in $pH $ of the solution will affect the rate of reaction (iv) doubling the concentration of $H^{+}$ ions will increase the reactions rate by 4 times.

In pseudo unimolecular reactions,

In the simple reaction $2A + B\to A_2B$, if the concentration of A is doubled and of B is halved, then the rate of reaction will

One mole of $N_2O_4$ gas at 300 K is kept in a closed container at 1 atm. It is heated to 600 K when 20 percent by mass of $N_2O_4$ decomposes to $NO_2(g)$. The resultant pressure in the container would be

$T$ is the half life period and $T_a$ is the average life of a radioactive substance. Which of the following statement is correct ?

The half life period of $Pb^{210}$ is 22 years. If 2g of $Pb^{210}$ is taken, then after 11 years the amount of $Pb^{210}$ will be present i

The rate constant of a zero order reaction is $0.2\, mol\, dm^{-3}\, hr^{-1}$. If the concentration of the reactant after 30 min is $0.05\, mol\, dm^{-3.}$ Then its initial concentration would

The rate law for the reaction 2X + Y $\to$ Z is Rate = k[X] [YJ].The correct statement with regard to this relation is

The rate of a certain reaction increases by 2.3 times when the temperature is raised from 300 K to 310K. If k is the rate constant at 300 K then the rate constant at 310 K will be equal to

The relation between half life $T_{1/2}$ of a radioactive sample and its mean life x is

Under what conditions a bimolecular reaction may be of first order?

Which of the following options does not show instantaneous rate of reaction at $40^{th}$ second?

Which of the following is an example of a fractional order reaction?

A hypothetical reaction $A_{2}+B_{2} \rightarrow 2 A B$ follows the mechanism as given below, $\left.A_{2} \rightleftharpoons A+A \text { (fast }\right) $ $A+B_{2} \longrightarrow A B+B \text { (slow) } $ $A+B \longrightarrow A B \text { (fast) }$ The order of the overall reaction is

For which order half-life period is independent of initial concentration?

The rate constant for the first order reaction is $ 60\text{ }{{s}^{-1}} $ . How much time will it take to reduce the concentration of the reactant to $ \frac{1}{16} $ th value?

The rate of reaction $ CC{{l}_{3}}CHO+NO\xrightarrow[{}]{{}}CHC{{l}_{3}}+NO+CO $ Is equal to rate $ =k[CC{{l}_{3}}CHO][NO] $. If concentration is expressed in $ mol\text{ }{{L}^{-1}}, $ the unit of $ k $ is

For the following homogeneous reaction, the unit of rate constant is: $A+B {->[k]}C$