The rate constant for a reaction of zero-order in A is 0.0030 mol L^-1 s^-1. How long will it take for the initial concentration of A to fall from 0.10 M to 0.075 M?

1. 8.3 sec

2. 0.83 sec

3. 83 sec

4. 10.3 sec

A first-order reaction is 15 % completed in 20 minutes. The amount of time required to complete 60 % of the reaction is:

When the concentration of reactant was made 4 times rate of reaction becomes 8 times. The order of reaction with respect to that reactant is 

1. 2

2. 3

3. 1

4. 1.5

The effect of a catalyst in a chemical reaction is to change the 

1. Acivation energy.

2. Equilibrium concentration.

3. Heat of reaction.

4. Final products.

The rate constant is given as \(K = 1.2 \times 10^3~mol^{-1} L^{-1} s^{-1}\), and the activation energy is \(E_a = 2.0 \times 10^2 ~kJ mol^{-1}\). As temperature T approaches infinity, what is the value of the pre-exponential factor (A)?

1. \(2.0 \times 10^2 \mathrm{~mol}^{-1} \mathrm{~L}^{-1} \mathrm{~s}^{-1}\)
2. \(1.2 \times 10^3 \mathrm{~mol}^{-1} \mathrm{~L}^{-1} \mathrm{~s}^{-1}\)
3. \(3.3 \times 10^3 \mathrm{~mol}^{-1} \mathrm{~L}^{-1} \mathrm{~s}^{-1}\)
4. \(2.4 \times 10^3 \mathrm{~mol}^{-1} \mathrm{~L}^{-1} \mathrm{~s}^{-1}\)

Assertion : If the activation energy of reaction is zero temperature will have no effect on the rate constant.

Reason : Lower the activation energy fasten is the reaction.

Assertion : For a reaction $\mathrm{A}\left(\mathrm{g}\right)\to \mathrm{B}\left(\mathrm{g}\right)$

                                 $—{\mathrm{r}}_{\mathbf{e}}=2.5 {\mathrm{P}}_{\mathrm{A}} \mathrm{at} 400\mathrm{K}$

                                 $—{\mathrm{r}}_{\mathbf{e}}=2.5 {\mathrm{P}}_{\mathrm{A}} \mathrm{at} 600\mathrm{K}$

                  activation energy is 4135 J/mol.

Reason : Since for any reaction, values of rate constant at two different temp is same therefore

               activation energy of the reaction is zero.

The units of rate constant and rate of reaction are same for: 

1. First order reaction 

2. Second order reaction 

3. Third order reaction 

4. Zero order reaction 

If concentration are measured in mole/litre and time in minutes , the unit for the rate constant of a $3^{rd}$ order reaction are

(1) $mol li{t}^{-1} mi{n}^{-1}$                                              

(2) $li{t}^2 mo{l}^{-2}mi{n}^{-1}$

(3) $lit mo{l}^{-1}mi{n}^{-1}$                                              

(4) $mi{n}^{-1}$

The following reaction was carried out at 300 K.

2SO₂(g)  +  O₂(g) →  2SO₃(g)

The rate of formation of $S{O}_3$ is related to the rate of disappearance of $O_2$  by the following expression:

1. $-\frac{∆\left[O_2\right]}{∆t}=+\frac{1}{2}\frac{∆\left[S{O}_3\right]}{∆t}$                           

2. $-\frac{∆\left[O_2\right]}{∆t}=\frac{∆\left[S{O}_3\right]}{∆t}$

3. $-\frac{∆\left[O_2\right]}{∆t}=-\frac{1}{2}\frac{∆\left[S{O}_3\right]}{∆t}$                           

4. None of the above.