Question

all alkalis are bases, but not vice versa. comment

Answer 1

hi dear mate

according to my knowledge
A substance which can ionize to give OH ions is a base (Arrhenius); A substance which accepts H+ is a base (Bronsted-Lowry); A substance which accepts a pair of electrons is a base (Lewis). Any substance which falls into anyone or more than one of these definitions is a base. An alkali is a special type of base which is soluble in water. Every base is not an alkali. see whether you can understand these statements:- "EVERY ALKALI IS A BASE BUT EVERY BASE IS NOT AN ALKALI" Thus you can see that you cannot say that base doesnt dissolve in water. It is just that we have a special name for bases which dissolve in water to give OH ions: alkali. A base may or may not give OH in water or even may or may not be soluble in water, but an alkali always has both these properties. Ca(OH)2, NaOH, Ba(OH)2 are base as well as alkali but NH3 is only a base (Bronsted) not alkali. The main thing is that a base which is soluable in water is an alkali whereas a base which is not soluable in water is not an alkali.

hope u got it