Organic acids are defined as organic compounds with acidic properties. Because these acids are organic, their structure must contain a carbon atom. Carboxylic acid, with the molecular formula as RCOOH, is one of the most common organic acids. Sulfonic acid and alcohol are also organic acids. Generally speaking, organic acids are weak acids, which can only partially ionize in solution. Organic acids are widely used in food industry. For example, citric acid is widely used in sodas and canned tomatoes and acetic acid is well known organic acid used for making vinegar. Organic acids are also as additives in pharmaceutical production, leather tanning.