The activation energy for the forward reaction A → B is Ea.
Which of the following statements about the activation energy for the reverse reaction is correct?
1. It is the negative of Ea
2. It is always less than Ea
3. It can be less than or more than Ea
4. It is always double of Ea
The reaction A → B follows first-order kinetics. The time taken for 0.8 mol of A to produce 0.6 mol of B is 1 hour. The time taken for the conversion of 0.9 mol of A to produce 0.675 mol of B will be:
| 1. | 1 hour | 2. | 0.5 hour |
| 3. | 0.25 hour | 4. | 2 hour |
If the rate of the reaction is equal to the rate constant, the order of the reaction is:
| 1. | 0 | 2. | 1 |
| 3. | 2 | 4. | 3 |
The temperature dependence of the rate constant (k) of a chemical reaction is written in terms of the Arrhenius equation,
k = A.e–E*/RT. The activation energy (E*) of the reaction can be calculated by plotting:
1.
2.
3.
4.
The radioisotope, tritium has a half-life of 12.3 years. If the initial amount of tritium is 32 mg, how many milligrams of it would remain after 49.2 years:
| 1. | 1 mg | 2. | 2 mg |
| 3. | 4 mg | 4. | 8 mg |
The decomposition of NH3 on a platinum surface is a zero-order reaction. The rates of production of N2 and H2 will be respectively:
(given ; k = 2.5 × 10–4 mol–1 L s–1 )
| 1. | 2.5 × 10−4 mol L−1 s−1 and 5.5 × 10−4 mol L−1 s−1
|
| 2. | 2.5 × 10−4 mol L−1 s−1 and 7.5 × 10−4 mol L−1 s−1
|
| 3. | 1.5 × 10−4 mol L−1 s−1 and 4.5 × 10−4 mol L−1 s−1
|
| 4. | 0.5 × 10−4 mol L−1 s−1 and 3.5 × 10−4 mol L−1 s−1 |
The rate equation of a reaction is expressed as, Rate = \(k(P_{CH_{3}OCH_{3}})^{\frac{3}{2}}\)
(Unit of rate = bar min–1)
The units of the rate constant will be:
1. bar1/2 min
2. bar2 min–1
3. bar–1 min–2
4. bar–1/2 min–1
The factor(s) that affect the rate of a chemical reaction is/are:
| 1. | Concentration/Pressure of reactants. |
| 2. | Temperature. |
| 3. | Presence of a catalyst. |
| 4. | All of the above. |
Which of the following statements regarding the rate constant of a reaction is correct?
| 1. | The rate constant approximately doubles with an increase in temperature of 10 °C |
| 2. | The rate constant becomes half with an increase in temperature of 10 °C |
| 3. | The rate constant remains unchanged with a rise in temperature by 10 °C |
| 4. | None of the above |
| t/s | 0 | 30 | 60 | 90 |
| [Ester]/mol L–1 | 0.55 | 0.31 | 0.17 | 0.085 |