Answerhydrogen ions from the acid react with hydroxide ions from the alkali to form water.
H+. + OH- —> H20
ExplanationIt is important to remember that when an acid reacts with an alkali, this is called a neutralisation reaction. A neutralisation reaction is always:Acid + Alkali —> Salt + WaterHowever, because the question is asking for ions, there is no salt. Acids are H+ ions (this gives them acidic properties) and alkalis are OH- ions (this gives them alkaline properties), and together they react to form water.