For the reaction: 2A + B → A2B | Class 12 Chemistry Chapter Chemical Kinetics, Chemical Kinetics NCERT Solutions

Question:

For the reaction:

2A + B → A2B

the rate = k[A][B]2with k= 2.0 x 10-6mol-2L2s-1. Calculate the initial rate of the reaction when [A] = 0.1 mol L-1, [B] = 0.2 mol L-1. Calculate the rate of reaction after [A] is reduced to 0.06 mol L-1.

Answer:

The initial rate of the reaction is

Rate = k [A][B]2

= (2.0 × 10 - 6mol - 2L2s - 1) (0.1 mol L - 1) (0.2 mol L - 1)2

= 8.0 × 10 - 9mol - 2L2s - 1

When [A] is reduced from 0.1 mol L - 1to 0.06 mol - 1, the concentration of A reacted = (0.1 - 0.06) mol L - 1 = 0.04 mol L - 1

Therefore, concentration of B reacted= 1/2 x 0.04 mol L-1 = 0.02 mol L - 1

Then, concentration of B available, [B] = (0.2 - 0.02) mol L - 1

= 0.18 mol L - 1

After [A] is reduced to 0.06 mol L - 1, the rate of the reaction is given by,

Rate = k [A][B]2

= (2.0 × 10 - 6mol - 2L2s - 1) (0.06 mol L - 1) (0.18 mol L - 1)2

= 3.89 mol L - 1s - 1


Study Tips for Answering NCERT Questions:

NCERT questions are designed to test your understanding of the concepts and theories discussed in the chapter. Here are some tips to help you answer NCERT questions effectively:

  • Read the question carefully and focus on the core concept being asked.
  • Reference examples and data from the chapter when answering questions about Chemical Kinetics.
  • Review previous year question papers to get an idea of how such questions may be framed in exams.
  • Practice answering questions within the time limit to improve your speed and accuracy.
  • Discuss your answers with your teachers or peers to get feedback and improve your understanding.

Comments

  • dinchak pooja
  • 2019-09-21 05:22:19

oohhhooo AHhhaa


  • Shubhangee
  • 2019-09-10 17:31:11

How come we halved the concentration of A to find the new one of B


  • Yyy
  • 2019-06-05 15:47:16

Ohho


  • Aynal Hoque
  • 2018-10-23 11:05:31

Second part of this answer\'s method is correct but answer is wrong...it will be = 3.888*10^-9 mol-2L2s-1


Comment(s) on this Question

Welcome to the NCERT Solutions for Class 12 Chemistry - Chapter . This page offers a step-by-step solution to the specific question from Excercise 2 , Question 2: For the reaction: 2A + B → A2B the rate = k[A][B]2with k= 2.0 x 10-6mol-2L2s-1. Calculate....