Final answer:
Being alkaline means having a high pH value above 7.0, with the human blood being slightly alkaline at pH 7.4 and common substances like baking soda being alkaline with a pH of around 9.0.
Step-by-step explanation:
Being alkaline means having a high pH value above 7.0 on the pH scale. For instance, water is neutral with a pH of 7.0, whereas substances with a pH above 7.0, ranging from 7.1 to 14.0, are considered alkaline or basic. This includes common household substances such as baking soda, with a pH of around 9.0. The human body also experiences variations in pH with blood being slightly alkaline with a pH of 7.4, which is maintained by the bicarbonate buffering system. On the other hand, the stomach environment is highly acidic with a pH between 1 to 2.