CBSE Class 12 Chemistry - Chemical Kinetics VBQs

Scroll down for PDF

CBSE Class 12 Chemistry - Chemical Kinetics VBQs Based on CBSE and NCERT guidelines. Value based questions are now being given in exams to promote morals and values in students, Students should read and understand the following VBQs to get better understanding and score good marks in exams

Chapter-4

CHEMICAL KINETICS

1. A catalyst is a substance that enhances the rate of a reaction. There are two types of catalysis i.e., homogeneous and heterogeneous. The heterogeneous catalysis is an important application in automobile catalytic converters.

Answer the following questions:

(i) As a student of chemistry, what chemical process do you think occurs in the heterogeneous catalysis in the converters?

(ii) Why the use of such catalytic converters in the vehicles is important?

(iii) What environmental values are associated with the use of such converters?

Ans:(i) The use of heterogeneous catalysis in automobile exhausts helps to reduce polluting gases, NO and CO which are responsible for photochemical smog.

(ii) The catalytic converter, which is a part of automobile exhaust system, oxidises CO to CO2 and NO to NO2 gas.

(iii) Value: Awareness of environmental pollution caused by highly toxic gases like CO and NO.

2. On one winter morning Sudha’s mother received a phone call from a close relative stating that three of them would be coming over for lunch. Sudha’s mother noticed that she did not have enough curd to serve the guests. Sudha, a class XII student suggested that her mother could warm the milk from the refrigerator or keep it under direct sunlight and curdle it.

a) Will it be helpful if her mother follows Sudha’s suggestion? How

b) Why is curdling of milk slower during winter?

c) What values are associated with Sudha’s suggestion?

Ans (a)Yes, because a rise in temperature (to an optimum value only) increases the rate of curdling.

(b) As per collision theory, a reaction takes place by collision of reacting particles. At lower temp collisions between the particles are less in number 

(c)Ability to take quick decisions at right moment, helping mentality, awareness of scientific principles lying behind domestic activities, presence of mind.

3. Teacher asked two Students ‘A’ and ‘B’ to demonstrate the reaction between Aluminium and dilute Sulphuric acid to the class. She provided the following chemicals for the experiment: Al foil, Al powder & dilute Sulphuric acid.Student A chose Al foil & dilute Sulphuric acid. Student B chose Al powder & dilute Sulphuric acid.

a) Who according to you has made the correct choice of chemicals?

b) Give a reason to justify the correct choice.

c) What value do you associate with the above? 

Ans: (a) Student B has made the correct choice.

(b) Al powder has larger surface area than the Al foil and hence it can react faster.

(c) Scientific awareness about factors affecting rate of reactions, ability to apply the gained knowledge in a different situations.

Please refer to the link below for CBSE Class 12 Chemistry - Chemical Kinetics VBQs

Tags: 


Click on the text For more study material for Chemistry please click here - Chemistry

Latest NCERT & CBSE News

Read the latest news and announcements from NCERT and CBSE below. Important updates relating to your studies which will help you to keep yourself updated with latest happenings in school level education. Keep yourself updated with all latest news and also read articles from teachers which will help you to improve your studies, increase motivation level and promote faster learning

CBSE Counseling for Board exam 2020 starts today

The 23rd psychological Counseling starts 1st February (today) for The Class10 and Class12 CBSE students and their parents, by the Central Board of Secondary Education (CBSE).    This Counseling service is cost-free and this counseling service will be available every...

CBSE Board Exam Date Sheet of class 10th and 12th

The Central Board of Secondary Education (CBSE) released the Date sheet of Class 10 and Class 12th 2020 examination on the official website cbse.nic.in. The board examination of Class 12 will be conducted from 15 February to 30 March 2020, while the board examination...

Simple tips to Excel in Examinations

We are entering the last quarter of the Academic Session. With examinations just around the corner, I am sure all of us are carrying a mixed bag of Stress, Excitement, and Anxieties!! So, first and foremost- Let’s be Positive and Futuristic! It’s most important to...

×
Studies Today