25-minute Test : Part XIII Industrial Chemistry

Vitamin C is an oxygen-rich carbon compound. The structure of it is shown in the diagram. Which of the following statements concerning vitamin C is/are correct?

(1) Its chemical name is ascorbic acid.

(2) It can be produced from glucose by fermentation using yeast.

(3) Its molecules have one chiral carbon atom.

• A. (1) only
• B. (2) only
• C. (1) and (3) only
• D. (2) and (3) only

The decomposition of nitrogen dioxide to nitrogen monoxide and oxygen is a second order reaction. The rate equation is: rate = k[NO₂(g)]², where k represents the rate constant. Given that the unit of the reaction rate is mol dm⁻³ s⁻¹, what is the unit of the rate constant?

• A. s⁻¹
• B. mol dm⁻³ s⁻¹
• C. mol⁻² dm⁶ s⁻¹
• D. mol⁻¹ dm³ s⁻¹

Which of the options is the concentration-time graph for a zeroth order reaction that involves only one reactant, X?

• A
• B
• C
• D

Three trials of an experiment were performed under the same experimental conditions to study the kinetics of the following reaction:

X(aq) + Y(aq) → Z(aq)

The table shows the data obtained. Which of the following is the rate equation of this reaction?

• A. Rate = k[X(aq)][Y(aq)]²

• B. Rate = k[X(aq)][Y(aq)]

• C. Rate = k[Y(aq)]

• D. Rate = k[X(aq)]

Which of the following statements explains why the rate of a gaseous reaction increases as the temperature increases?

• A. The volume of the reaction system increases.
• B. The number of gaseous particles in the system increases.
• C. The fraction of particles with kinetic energy greater than the activation energy increases.
• D. The fraction of particles colliding in the proper orientation increases.

An experiment was carried out to study the kinetics of the fermentation of a sugar solution in the presence of an enzyme. The table shows the concentration of the sugar solution at three different times during the experiment. Which of the following statements about the fermentation is correct?

• A. The concentration of the sugar solution decreases uniformly with time.
• B. The concentration of the sugar solution decreases more quickly as the reaction proceeds.
• C. The rate of the fermentation is a constant throughout the reaction.
• D. The rate of the fermentation decreases as the concentration of the sugar solution decreases.

Consider the reaction as shown. Experimentally, the order of reaction with respect to I₂(aq) is zero. Which of the following statements concerning the reaction are correct?

(1) The concentration of I₂(aq) decreases linearly with time.

(2) The rate of change in concentration of I₂(aq) remains constant throughout the reaction.

(3) Increasing the concentration of I₂(aq) will increase the rate of the reaction.

• A. (1) and (2) only
• B. (1) and (3) only
• C. (2) and (3) only
• D. (1), (2) and (3)

Refer to the energy profile for the reversible reaction ‘P(g) ⇌ Q(g) + R(g)’. What is the activation energy of the backward reaction?

• A. 20 kJ mol⁻¹
• B. 80 kJ mol⁻¹
• C. 100 kJ mol⁻¹
• D. 120 kJ mol⁻¹

• A. (1) only
• B. (2) only
• C. (1) and (3) only
• D. (2) and (3) only

The rate constant of a reaction is found to triple when the temperature is increased from 298 K to 308 K. What is the activation energy of the reaction?

(Given R = 8.31 J K⁻¹ mol⁻¹)

• A. 125.6 kJ mol⁻¹
• B. 83.7 kJ mol⁻¹
• C. 57.0 kJ mol⁻¹
• D. 22.9 kJ mol⁻¹