Acidity refers to the sour or tart taste of a substance, often caused by the presence of acid.
It can also refer to the degree of acidity or alkalinity in a solution, measured using the pH
scale. Acidity is often associated with sour foods, such as citrus fruits, vinegar, and
fermented foods. It can also have various practical applications, such as in cooking,
preserving, and leavening foods. Acidity can also have negative effects, such as causing
heartburn or food poisoning if food is not properly preserved.