Class 11th

Also known as arenes, they are a special category of hydrocarbons that have a ring-like structure. These hydrocarbons consist of delocalized pie electrons and are known to be very stable. Benzene is known to be the simplest aromatic hydrocarbon 

Paraffin is a term derived from the latin literature meaning low reactivity or little affinity. This term is generally used to denote alkanes because out of all the hydrocarbons, they have the least reactivity because of having a strong carbon bond between their atoms.

In the medical entrance test NEET, there can be 1 to 3 questions from this chapter. Some year, the Chemistry section of NEET has only one question from this chapter and in some other years, there can be 3 questions.

The following are the key concepts of this chapter: Compound, Elements, Rules, Law of conservation of mass, Addition and Subtraction, Atomic Mass, Law of multiple proportions, and Molecular Mass.

As the name suggests, the first chapter of the NCERT Class 11 Chemistry introduces various basic concepts of chemistry, such as the definition and importance of chemistry, atomic matter and molecular masses, the mole concept, laws of chemical combination, empirical, stoichiometry, and molecular formulas. It also includes the concepts of molarity and molality.

Correct order of reducing character is

NH₃< PH₃< AsH₃< SbH₃< BiH₃

It may vary, depending on the type of substance you are talking about. Some can have their carcinogenic/toxic levels reduced and some may not. Some processes involve detoxification, overheating, altering the chemical structure etc. You can also yourself avoid exposure to these substances by adopting healthy lifestyle habits like jogging, yoga, exercising, sports, meditation etc. and staying away from cigarettes, alcohol, tobacco and others.