Acids are the substances which taste sour, change blue litmus red, are corrosive to metals and furnish H+ ions in their aqueous solutions. Bases are the substances which taste bitter, change red litmus blue, feel slippery and furnish OH– ions in their aqueous solutions.
The basic cause of chemical bonding is to attain noble gas configuration either by transfer of electron from a metal to non-metal or by sharing of electrons between two non-metal atoms. All the atoms have a tendency to acquire stable state or noble gas configuration and is called Octet Rule.
A chemical equation is a shorthand description of a reaction. It symbolically represents the reactants, products and their physical states. In a balanced chemical equation, number of atoms of each type involved in the chemical reaction is equal on the reactants and products sides of the equation.
Measurement is a process of comparing a physical quantity with a standard quantity. The standard quantity used to compare a physical quantity for its measurement is called unit. The internationally accepted modern system of units used in science is known as SI units.