Consider the graph given in the figure. Which of the following options does not show an instantaneous rate of reaction in the 40s?
1. \({V_5 -V_2 \over 50-30}\)
2. \({V_4 -V_2 \over 50-30}\)
3. \({V_3 -V_2 \over 40-30}\)
4. \({V_3 -V_1 \over 40-20}\)
True statement among the following is:
1. | The rate of a reaction decreases with the passage of time as the concentration of reactants decreases. |
2. | The rate of a reaction is the same at any time during the reaction. |
3. | The rate of a reaction is independent of temperature change. |
4. | The rate of a reaction decreases with an increase in the concentration of the reactants. |
The correct expression for the rate of reaction given below is:
\(5 \mathrm{Br}^{-}(\mathrm{aq})+\mathrm{BrO}_3^{-}(\mathrm{aq})+6 \mathrm{H}^{+}(\mathrm{aq}) \rightarrow 3 \mathrm{Br}_2(\mathrm{aq})+3 \mathrm{H}_2 \mathrm{O}(\mathrm{l})\)
1. | \(\frac{\Delta\left[B r^{-}\right]}{\Delta t}=5 \frac{\Delta\left[H^{+}\right]}{\Delta t} \) | 2. | \(\frac{\Delta\left[\mathrm{Br}^{-}\right]}{\Delta t}=\frac{6}{5} \frac{\Delta\left[\mathrm{H}^{+}\right]}{\Delta t} \) |
3. | \(\frac{\Delta[\mathrm{Br^-}]}{\Delta t}=\frac{5}{6} \frac{\Delta\left[\mathrm{H}^{+}\right]}{\Delta t} \) | 4. | \(\frac{\Delta\left[\mathrm{Br}^{-}\right]}{\Delta t}=6 \frac{\Delta\left[\mathrm{H}^{+}\right]}{\Delta t}\) |
The correct representation of an exothermic reaction is:
1. | 2. | ||
3. | 4. | Both 1 and 2 |
Rate law for the reaction \(A+2 B \rightarrow C\) is found to be
Rate = k[A][B]
If the concentration of reactant 'B' is doubled, keeping the concentration of A constant, then the value of the rate of the reaction will be:
1. | The same. | 2. | Doubled. |
3. | Quadrupled. | 4. | Halved. |
An incorrect statement about the collision theory of chemical reaction is:
1. | It considers reacting molecules or atoms to be hard spheres and ignores their structural features. |
2. | The number of effective collisions determines the rate of reaction. |
3. | The collision of atoms or molecules possessing sufficient threshold energy results in product formation. |
4. | Molecules should collide in the proper orientation for the collision to be effective with sufficient threshold energy and proper orientation. |
A first-order reaction is 50 % completed in 1.26 × 1014 s. The time required for 100 % completion of the reaction will be:
1. 1.26 × 1015 s
2. 2.52 × 1014 s
3. 2.52 × 1028 s
4. Infinite
Compounds A and B react according to the following chemical equation.
A(g) + 2B(g) 2C(g)
The concentration of either A or B was changed keeping the concentrations of one of the reactants constant and rates were measured as a function of initial concentration. The following results were obtained. Choose the correct option for the rate equations for this reaction.
Experiment | Initial concentration of [A]/mol L–1 |
Initial concentration of [B]/moI L–1 |
Initial rate (mol L–1 s–1) |
1. 2. 3. |
0.30 0.30 0.60 |
0.30 0.60 0.30 |
0.10 0.40 0.20 |
An incorrect statement regarding the catalyst is:
1. | It catalyzes the forward and backward reactions to the same extent. |
2. | It alters gibbs free energy of the reaction. |
3. | It is a substance that does not change the equilibrium constant of a reaction. |
4. | It provides an alternate mechanism by reducing activation energy between reactants and products. |
The value of the rate constant of a pseudo-first-order reaction:
1. | Depends on the concentration of reactants present in a small amount. |
2. | Depends on the concentration of reactants present in excess. |
3. | Is independent of the concentration of reactants. |
4. | Depends only on temperature. |