Answer:
neutralise
Explanation:
There is a special name given to the reaction between an acid and a base to form salt and water and water only. That name is 'neutralization'. Hence to 'neutralize' an acid connotes the idea of 'cancelling' the effect of an acid.
An acid has a number of deleterious effects on surfaces, the most prominent of which is corrosion of the surface due to oxidation. If a surface is accidentally exposed to an acid, the effect of that acid on the surface can be counteracted by the immediate application of a base to 'neutralize' the acid. Neutralization in this sense is akin to 'cancelling' out the acid.
The examples are endless. Another common example is the neutralization of an acidic soil by a base in order to 'cancel' the acidity of the soil and make the soil fertile for plant growth.
