howard is working with a cleaning solution that contains sodium hydroxide. although he is using gloves, when he pours the solution to dilute it for cleaning use, he spills a bit on his arm. his arm feels slimy to the touch and now has a burn mark. what is the chemical route of entry?

Howard's chemical exposure to sodium hydroxide (NaOH) solution caused a skin injury characterized by a slimy feeling and a burn mark. The chemical route of entry in this case is absorption through the skin (dermal exposure). Sodium hydroxide is a highly corrosive alkaline substance that can penetrate the skin, disrupting proteins and fats, leading to liquefactive necrosis and chemical burns

. When sodium hydroxide contacts the skin, it reacts with moisture and lipids, breaking down the skin barrier and causing immediate irritation, redness, and pain. The "slimy" sensation is due to the alkaline nature of NaOH reacting with skin components. This can progress to soft, moist burns and ulcerations, as the chemical penetrates deeper layers of the skin

. The burn mark Howard experiences is consistent with this corrosive effect. Thus, the chemical route of entry is:

• Dermal absorption/contact : Sodium hydroxide penetrates the skin, causing chemical burns and tissue damage

Other routes such as inhalation or ingestion are not relevant here since the exposure was localized to the skin. Immediate rinsing with water is critical to reduce damage and prevent further injury

. In summary, Howard's injury resulted from sodium hydroxide entering his body through skin contact, causing a corrosive chemical burn via dermal absorption.