Science Olympiad Water Quality Practice Test 2026 - Free Water Quality Practice Questions and Study Guide

The chemical formula for bicarbonate is HCO3-. This ion is a crucial component in various biochemical processes, especially in the regulation of pH in biological systems. Bicarbonate acts as a buffer in the body, helping to maintain acid-base balance.

When carbon dioxide (CO2) dissolves in water, it can combine with water (H2O) to form carbonic acid (H2CO3). Carbonic acid can then partially dissociate into bicarbonate (HCO3-) and hydrogen ions (H+), which illustrates its significance as a buffer. The presence of bicarbonate in natural waters is essential for aquatic life, as it helps stabilize pH levels in ecosystems.

In contrast, H2CO3 represents carbonic acid itself, while CO3^2- refers to the carbonate ion, which is related but different from bicarbonate. H2O is simply water and does not represent any carbonate species. Understanding the distinct roles and forms of these compounds is important when studying water quality and its chemical dynamics.