What is the definition of a lewis base? a substance that donates a proton a substance that donates electrons to form a covalent bond a substance that accepts electrons to form a covalent bond a substance that when dissolved in water increases hydrogen ion concentration?

A Lewis base is a substance that donate electron to form a covalent bond. A Lewis base can be a compound or an ionic species which is capable of donating an electron pair to an acceptor compound. An atom, ion or molecule with a lone pair can be a Lewis base. Lewis bases are nucleophillic in action, that is, they attack positive charges with their lone pairs.