Catalysts are used to increase the rate of a chemical reaction. Because it

Half-life of a first order reaction is 20 seconds and initial concentration of reactant is 0.2 M . The concentration of reactant left after 80 seconds is

$$ \text { In the given graph, } \mathrm{E}_{\mathrm{a}} \text { for the reverse reaction will be } $$

For the reaction $2 \mathrm{~N}_2 \mathrm{O}_{5(\mathrm{~g})} \rightarrow 4 \mathrm{NO}_{2(\mathrm{~g})}+\mathrm{O}_{2(\mathrm{~g})}$ initial concentration of $\mathrm{N}_2 \mathrm{O}_5$ is $2.0 \mathrm{molL}^{-1}$ and after 300 min , it is reduced to $1.4 \mathrm{molL}^{-1}$. The rate of production of $\mathrm{NO}_2\left(\mathrm{in} \mathrm{molL}^{-1} \mathrm{~min}^{-1}\right)$ is

For the reaction, $A \rightleftharpoons B, E_a=50 \mathrm{~kJ} \mathrm{~mol}^{-1}$ and $\Delta H=-20 \mathrm{~kJ} \mathrm{~mol}^{-1}$. When a catalyst is added $E_a$ decreases by $10 \mathrm{~kJ} \mathrm{~mol}^{-1}$. What is the $E_a$ for the backward reaction in the presence of catalyst?

For the reaction, $\mathrm{PCl}_5 \longrightarrow \mathrm{PCl}_3+\mathrm{Cl}_2$, rate and rate constant are $1.02 \times 10^{-4} \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$ and $3.4 \times 10^{-5} \mathrm{~s}^{-1}$ respectively at a given instant. The molar concentration of $\mathrm{PCl}_5$ at that instant is

Which one of the following does not represent Arrhenius equation?

In which one of the following reactions, rate constant has the unit $$\mathrm{mol} \mathrm{~L}^{-1} \mathrm{~s}^{-1}$$ ?

For a reaction, the value of rate constant at $$300 \mathrm{~K}$$ is $$6.0 \times 10^5 \mathrm{~s}^{-1}$$. The value of Arrhenius factor $$A$$ at infinitely high temperature is

The rate constant $$k_1$$ and $$k_2$$ for two different reactions are $$10^{16} \times e^{-2000 / T}$$ and $$10^{15} \times e^{-1000 / T}$$ respectively. The temperature at which $$k_1=k_2$$ is

For $$n$$th order of reaction, half-life period is directly proportional to

Half-life of a reaction is found to be inversely proportional to the fifth power of its initial concentration, the order of reaction is

A first order reaction is half completed in $$45 \mathrm{~min}$$. How long does it need $$99.9 \%$$ of the reaction to be completed?

The rate of the reaction, $$\mathrm{CH}_3 \mathrm{COOC}_2 \mathrm{H}_5+\mathrm{NaOH} \longrightarrow \mathrm{CH}_3 \mathrm{COONa}+\mathrm{C}_2 \mathrm{H}_5 \mathrm{OH}$$ is given by the equation, rate $$=k\left[\mathrm{CH}_3 \mathrm{COOC}_2 \mathrm{H}_5\right][\mathrm{NaOH}]$$. If concentration is expressed in $$\mathrm{mol} \mathrm{L}^{-1}$$, the unit of $$k$$ is

For a reaction, $$A+2 B \rightarrow$$ Products, when concentration of $$B$$ alone is increased half-life remains the same. If concentration of $$A$$ alone is doubled, rate remains the same. The unit of rate constant for the reaction is

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

The rate of a gaseous reaction is given by the expression $$k[A][B]^2$$. If the volume of vessel is reduced to one half of the initial volume, the reaction rate as compared to original rate is

Higher order $$(>3)$$ reactions are rare due to

The time required for $$60 \%$$ completion of a first order reaction is $$50 \mathrm{~min}$$. The time required for $$93.6 \%$$ completion of the same reaction will be

For an elementary reaction $$2 A+3 B \rightarrow 4 C+D$$ the rate of appearance of $C$ at time '$$T$$' is $$2.8 \times 10^{-3} \mathrm{~mol} \mathrm{~L}^{-1} \mathrm{~S}^{-1}$$. Rate of disappearance of $$B$$ at '$$t$$' $t$ will be

The rate constant of a reaction is given by $$k=P Z e^{-E_a / R T}$$ under standard notation. In order to speed up the reaction, which of the following factors has to be decreased?

The plot of $$t_{1 / 2} \mathrm{~v} / \mathrm{s}~[R]_0$$ for a reaction is a straight-line parallel to $$X$$-axis. The unit for the rate constant of this reaction is

Which is a wrong statement?

1L of $$2 \mathrm{M~CH}_3 \mathrm{COOH}$$ is mixed with 1L of $$3 \mathrm{M} \mathrm{~C}_2 \mathrm{H}_5 \mathrm{OH}$$ to form an ester. The rate of the reaction with respect to the initial rate when each solution is diluted with an equal volume of water will be