Why is water produced in a neutralisation reaction?

Water is produced in a neutralisation reaction because it's the result of the combination of hydrogen ions and hydroxide ions.

In a neutralisation reaction, an acid reacts with a base to produce a salt and water. This happens because acids are substances that can donate a hydrogen ion (H+), while bases are substances that can accept a hydrogen ion. When an acid and a base react, the hydrogen ion from the acid combines with the hydroxide ion (OH-) from the base to form water (H2O).

The process of neutralisation is essentially a reaction between hydrogen ions and hydroxide ions. When these ions meet, they combine to form water, which is a neutral substance. This is why the reaction is called 'neutralisation' - because it results in the production of a neutral substance, water.

The chemical equation for a neutralisation reaction is: Acid + Base → Salt + Water. For example, if hydrochloric acid (HCl) reacts with sodium hydroxide (NaOH), the products will be sodium chloride (NaCl), which is a salt, and water. The equation for this reaction is: HCl + NaOH → NaCl + H2O.

In summary, water is produced in a neutralisation reaction because it's the product of the combination of hydrogen ions from the acid and hydroxide ions from the base. This reaction is fundamental to many processes in chemistry and is a key concept in IGCSE Chemistry.