According to lewis ,
“Base is a specie which can donate an electron pair to an acceptor compound.”
Example of lewis base:
Water,ammonia,etc are examples of lewis base.
Other properties of base:
¤Base is proton acceptor.
¤Bases when dissolve in water gives hydroxide ion.
¤Bases are bitter in taste.
¤Bases are slippery to touch.
¤Base can change the color of indicator.
¤Base changes the color of litmus paper from red to blue.
¤Any specie with PH greater than 7 is considered and base.
¤Base is used in the neutralization reaction ( the reaction between an acid and base and the product is salt nad water).