This  book,  ‘A  New  Comprehensive  Chemistry’  for  grade  XI,  is  a  result  of

long time experience in teaching chemistry for previous HSEB level of Nepal as well as advanced level in Tribhuvan University. In addition of this we also have published beneficial theoretical as well as experimental books in chemistry for grade XI and XII based on previous curriculum of the Board as we well as for Bachelor level Chemistry of Tribhuvan University within the domain of its curriculum. We, based on this experience, are pleased to present this new text book of chemistry for grade XI of secondary level school board examination Nepal covering the scope and depth completely with sequential order of chapters mentioned in its recent curriculum.

We have tried to define and explain all scientific and technical terms clearly in straightforward style avoiding unnecessary derogative expressions to give students a foundation for more advanced chemistry courses and we believe that our approach makes realistic demands on both student and instructor with a hope for the reward to be real.

The authors wish to acknowledge colleagues and well wishers with thank for their encouraging suggestion which help in the preparation of the final version of the text.

We express our deep indebtedness to Mr. Babu Ram Gautam, Managing Director of Heritage Publishers and Distributors for publishing this book within the record time. Similarly, we really appreciate Mr. Rajendra Neupane for his patience and praiseworthy computer setting. Finally we would like to thank our families for their patience and encouragement during the preparation of this book.