The strength of an alkali is determined by its concentration of hydroxide ions (OH-). The higher the concentration of hydroxide ions, the stronger the alkali. Concentrated alkalis have a higher concentration of hydroxide ions than dilute alkalis, so they are more corrosive and can cause more severe burns.
In addition, concentrated alkalis are more likely to react with other substances to produce hazardous fumes. For example, concentrated sodium hydroxide can react with hydrochloric acid to produce chlorine gas, which is a toxic gas that can cause respiratory problems.
For these reasons, it is important to take precautions when handling concentrated alkalis. Always wear gloves and eye protection, and work in a well-ventilated area. If you do come into contact with a concentrated alkali, immediately flush the affected area with water and seek medical attention.
