NEET Chemical Kinetics — Set 3

Question 1

For the reaction $ 2\text{A} + \text{B} \to 3\text{C} $, the rate of disappearance of B is $ 0.03 \, \text{mol L}^{-1} \text{min}^{-1} $. What is the rate of formation of C?

Accepted Answer

Rate = $ -\frac{\Delta[\text{B}]}{\Delta t} = \frac{1}{3} \frac{\Delta[\text{C}]}{\Delta t} $. Given: $ -\frac{\Delta[\text{B}]}{\Delta t} = 0.03 \, \text{mol L}^{-1} \text{min}^{-1} $. $ \frac{\Delta[\text{C}]}{\Delta t} = 3 \times 0.03 = 0.09 \, \text{mol L}^{-1} \text{min}^{-1} $.

Question 2

A zero-order reaction takes 50 s to reduce the concentration from $ 0.2 \, \text{mol L}^{-1} $ to $ 0.15 \, \text{mol L}^{-1} $. What is the rate constant?

Accepted Answer

For zero-order, $ k = \frac{[\text{R}]_0 - [\text{R}]}{t} $. Given: $ [\text{R}]_0 = 0.2 \, \text{mol L}^{-1} $, $ [\text{R}] = 0.15 \, \text{mol L}^{-1} $, $ t = 50 \, \text{s} $. $ k = \frac{0.2 - 0.15}{50} = \frac{0.05}{50} = 1.0 \times 10^{-3} \, \text{mol L}^{-1} \text{s}^{-1} $.

Question 3

A reaction has the rate law $ \text{Rate} = k[\text{A}]^{2/3}[\text{B}]^{1/3} $. What is the overall order?

Accepted Answer

Overall order = $ \frac{2}{3} + \frac{1}{3} = \frac{3}{3} = 1 $.

NEET Chemistry: Chemical Kinetics — Practice Set 3

Q1. For the reaction \( 2\text{A} + \text{B} \to 3\text{C} \), the rate of disappearance of B is \( 0.03 \, \text{mol L}^{-1} \text{min}^{-1} \). What is the rate of formation of C?

Q2. A zero-order reaction takes 50 s to reduce the concentration from \( 0.2 \, \text{mol L}^{-1} \) to \( 0.15 \, \text{mol L}^{-1} \). What is the rate constant?

Q3. A reaction has the rate law \( \text{Rate} = k[\text{A}]^{2/3}[\text{B}]^{1/3} \). What is the overall order?

Q4. A first-order reaction has a half-life of 12 minutes. What is the time required for 90% completion?

Q5. A reaction’s rate increases by 2 times when the temperature rises from 310 K to 320 K. What is the activation energy (\( R = 8.314 \, \text{J mol}^{-1} \text{K}^{-1} \))?

Q6. A reaction’s rate increases by 16 times when the concentration of the reactant is increased by 4 times. What is the order of the reaction?

Q7. A reaction’s rate constant increases from \( 1.0 \times 10^{-3} \, \text{s}^{-1} \) at 25°C to \( 3.0 \times 10^{-3} \, \text{s}^{-1} \) at 35°C. What is the activation energy (\( R = 8.314 \, \text{J mol}^{-1} \text{K}^{-1} \))?

Q8. A pseudo-first-order reaction has a rate constant of \( 0.0693 \, \text{min}^{-1} \). What is its half-life?

Q9. A first-order reaction is 50% complete in 40 minutes. What is the time required for 90% completion?

Q10. A first-order reaction has a rate constant of \( 0.0231 \, \text{min}^{-1} \). What is the time for 99% completion?