Which acids are graded as 2 in the laboratory severity scale?

• A. Benzoic acid, Boric acid, Carbonic acid
• B. HCl and Nitric acid
• C. Hydrochloric acid
• D. Sulfuric acid

Answer: (A)

The main idea is that the lab severity grade reflects how corrosive or hazardous an acid is, which correlates with acid strength. Weak acids cause less harm and are considered milder, so they land at a mid-low severity level. Benzoic acid, boric acid, and carbonic acid are all weak acids: benzoic acid has a moderate tendency to donate protons (pKa around 4.2), boric acid is a mild acid in water (effective pKa about 9.2), and carbonic acid is a weak diprotic acid (pKa1 about 6.35). Their lower corrosivity means they’re assigned the grade 2.

In contrast, strong mineral acids like hydrochloric acid and nitric acid dissociate completely and release large amounts of H+, making them highly corrosive and hazardous, and sulfuric acid is also very corrosive, so those would be rated higher than 2.