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CBSE 12th Chemistry Case Study Based Questions: CBSE Board exam for class 12 Chemistry has been scheduled for February 27, 2024. It will have different types of questions, like MCQs, assertion-based questions, short-answer type questions, long-answer type questions, and case study based questions. To help the students of CBSE Class 12 Chemistry with case study-based questions, we have provided some important case study-based questions and answers. Practising these questions will help students score the best marks in board exams.
CBSE Class 12 Chemistry Paper Pattern
CBSE Class 12 Chemistry exam will be conducted for 70 marks. The time duration for students to attempt the paper will be 3 hours. All questions are compulsory. Use of log tables and calculators is not allowed.
| Section | Number of Questions & Type | Marks allotted per Question |
| Section A | 16 (MCQs) | 1 mark |
| Section B | 5 (Short answer questions) | 2 marks |
| Section C | 7 (Short answer questions) | 3 marks |
| Section D | 2 ( Case Study- Based Questions) | 4 marks |
| Section E | 3 (Long Answer Type Question) | 5 marks |
Important Case Study Based Questions for Class 12th Chemistry with Solutions
The following questions are case-based questions. Each question has an internal choice and carries 4 marks each. Read the passage carefully and answer the questions that follow.
Q.1. Many people believe that James Watson and Francis Crick discovered DNA in the 1950s. In reality, this is not the case. Rather, DNA was first identified in the late 1860s by Swiss chemist Friedrich Miescher. Then, in the decades following Miescher's discovery, other scientists--notably, Phoebus Levene and Erwin Chargaff--carried out a series of research efforts that revealed additional details about the DNA molecule, including its primary chemical components and the ways in which they joined with one another. Without the scientific foundation provided by these pioneers, Watson and Crick may never have reached their groundbreaking conclusion of 1953: that the DNA molecule exists in the form of a three-dimensional double helix. Chargaff, an Austrian biochemist, as his first step in this DNA research, set out to see whether there were any differences in DNA among different species. After developing a new paper chromatography method for separating and identifying small amounts of organic material, Chargaff reached two major conclusions: (i) the nucleotide composition of DNA varies among species. (ii) Almost all DNA, no matter what organism or tissue type it comes from maintains certain properties, even as its composition varies. In particular, the amount of adenine (A) is similar to the amount of thymine (T), and the amount of guanine (G) approximates the amount of cytosine (C). In other words, the total amount of purines (A + G) and the total amount of pyrimidines (C + T) are usually nearly equal. This conclusion is now known as "Chargaff's rule." Chargaff’s rule is not obeyed in some viruses. These either have single- stranded DNA or RNA as their genetic material. Answer the following questions: a. A segment of DNA has 100 adenine and 150 cytosine bases.
a. What is the total number of nucleotides present in this segment of DNA?
Ans. A = 100 so T = 100
C=150 so G = 150
Total nucleotides = 100+100+150+150 =500
b. A sample of hair and blood was found at two sites. Scientists claim that the samples belong to the same species. How did the scientists arrive at this conclusion?
Ans. They studied the nucleotide composition of DNA. It was the same so they concluded that the samples belong to the same species.
c. The sample of a virus was tested and it was found to contain 20% adenine, 20% thymine, 20 % guanine and the rest cytosine. Is the genetic material of this virus (a) DNA- double helix (b) DNA-single helix (c) RNA? What do you infer from this data?
Ans. A = T = 20%
But G is not equal to C so double helix is ruled out.
The bases pairs are ATGC and not AUGC so it is not RNA.
The virus is a single helix DNA virus.
The important case study-based questions with answers for CBSE Class 12 Chemistry can be accessed from the below-given PDF link:
Important Case Study Based Questions for Class 12th Chemistry with Solutions Download PDF |
Importance of Solving Case Study Questions for Class 12 Chemistry
- Case study-based questions in Class 12 are pivotal for good scores. Practicing these questions equips students to tackle these types of questions effectively.
- Solving case study-based questions helps students develop an efficient time management strategy.
- Excelling in Case study-based questions cultivates a holistic subject comprehension essential for future pursuits.
Among all the subjects, chemistry is considered one of the toughest because of the nature of the questions. Thus, this subject requires consistent practice. To score well in the final exams, students are advised to solve good number of questions.
Important Study Resources for CBSE Class 12 Chemistry Exam 2024
- CBSE Class 12 Chemistry Syllabus 2023-24
- CBSE Chemistry Sample Paper Class 12 2023-24
- Chemistry Additional Questions for CBSE Class 12
- CBSE Chemistry Previous Year Question Paper Class 12
- Top 30+ CBSE Class 12 Chemistry MCQs for Board Exam 2024 with Answers to Secure Good Marks
Also Read: CBSE Date Sheet 2024: Download Class 10 and 12 Revised Schedule in PDF