Dear Students, Heartiest congratulations to everyone on behalf of Udvash for successfully completing SSC level and moving on to HSC level. The higher secondary curriculum is much different and vast compared to the secondary curriculum. The specific NCTB ‘textbooks’ were the main focus of the SSC level, but there is no subject wise specific book at the HSC level. But there are lots of NCTB approved books written by different authors available in the market. Because of this reason, many students face a dilemma while selecting textbooks. Besides, though the syllabus at the HSC level is much vast compared to the SSC level, the time for taking preparation is very limited. So, this Parallel Text has been designed to save the students from dilemma and thus save their valuable time in this crucial phase. One of the main causes of frustration of many HSC candidates is that they cannot understand the theoretical discussion in the textbooks. So, many students lose interest in studying by understanding the concepts. As a result, many students fail to secure good grades at the HSC exam and the admission test. To make learning easier and interesting for you, the Parallel Text books have been written in easy-to-understand language accompanied by lots of practical examples, stories, cartoons, and figures. Mathematical examples have been incorporated after discussion on every topic; which will give an idea about the application of the topic and solving mathematical problems side by side with assisting to understand the next topics. For ease of understanding, the important definitions, characteristics, differences, etc. have been shown in a separate section. Besides, the most common mistakes have been highlighted under ‘Caution!’. But it is not enough to just understand the concepts, you also need enough practice. And to make this easier, the ‘Topic-wise Question and Answer from Previous Years’ section has been additionally incorporated at the end of some important topics from every chapter. And this sections consists of the solutions of previous years’ Board questions along with the questions from the admission tests of BUET, RUET, KUET, CUET, Medical and University of Dhaka. If you practice step-by-step in this way, you will be able to take full preparation for the Board exams and also prepare yourself for the admission tests simultaneously. Besides, ‘Important Practice Problems’ and ‘Mathematical Problems’ has been added at the end of every chapter, which you can practice to enrich your preparation. We hope our Parallel Text strengthen your basic idea about the concepts at HSC level and help you to secure A at the board exams in addition to being prepared for the admission tests. Best wishes for a prosperous life and a bright future- Udvash Chemistry Team