Describe the difference between bases and alkalis, and explain acid-alkali neutralisation reactions.

A base is a something that react with an acid to form water and a salt. An alkali is any base that is soluble in water. An acid in solution will form H+ ions as the acid splits. For example HCl in solution becomes H+ and Cl-. Alkaline solutions contain OH- ions from the alkali splitting. For example NaOH solution becomes Na+ and OH-. In an acid alkali neutralisation reaction the two react to form water (H2O) and a salt. The H+ ions react with the OH- ions to form the water and the salt is formed from the other componants. For example HCL + NaOH = H2O and NaCl because after you remove the H+ and OH- (as they react) leftover is Na+ and Cl-.