Introduction:
In the CBSE Board exam for class 12 Chemistry, the questions are primarily based on the NCERT textbook. The textbook is designed by experts and follows the curriculum set by the Central Board of Secondary Education (CBSE). The questions asked in the exam can be broadly categorized into two types - in-text questions and back exercise questions.

In-text Questions:
In-text questions are the ones that appear within the chapters of the NCERT textbook. These questions are designed to assess the understanding of the concepts explained in the chapter. While some of these questions may be straightforward and direct, others may require a deeper understanding and application of the concepts.

Back Exercise Questions:
Back exercise questions are provided at the end of each chapter in the NCERT textbook. These questions are designed to reinforce the concepts learned in the chapter and to assess the overall understanding of the topic. They cover a wide range of difficulty levels, from basic to advanced, and require students to apply the concepts in different scenarios.

Connection to CBSE Board Exam:
The CBSE Board exam for class 12 Chemistry is set by the board itself, and it is based on the curriculum outlined in the NCERT textbook. While the questions in the exam may not be an exact replica of the in-text and back exercise questions, they are designed to test the knowledge and understanding of the concepts covered in the NCERT textbook.

Importance of NCERT:
NCERT is considered the primary reference material for CBSE Board exams. The textbooks are carefully crafted to provide a comprehensive understanding of the subject and to prepare students for the board exams. Hence, it is crucial for students to thoroughly study the NCERT textbook and solve all the in-text and back exercise questions to perform well in the exam.

Additional Resources:
While the questions in the CBSE Board exam are primarily based on the NCERT textbook, it is beneficial for students to refer to additional resources like sample papers, previous year question papers, and reference books. These resources can help students familiarize themselves with the exam pattern, gain more practice, and expose them to a wider range of questions.

Conclusion:
While the questions asked in the CBSE Board exam for class 12 Chemistry are primarily based on the NCERT textbook, it is important to note that the questions may not be exactly the same as the in-text and back exercise questions. However, a strong understanding of the concepts covered in the NCERT textbook and regular practice of the in-text and back exercise questions will significantly enhance a student's chances of performing well in the exam.