Final answer:
Substances that tend to be alkaline are those that donate hydroxide ions (OH−) or absorb hydrogen ions (H+), causing a rise in pH. Strong bases like sodium hydroxide and common household cleaners are highly alkaline, while weak bases include seawater and baking soda.
Step-by-step explanation:
What Types of Substances Tend to Be Alkaline?
Alkaline substances, also known as bases, tend to be compounds that readily donate hydroxide ions (OH−) or take up hydrogen ions (H+). These substances, when dissolved in water, increase the pH level of the solution. Strong bases, like sodium hydroxide (NaOH), and many household cleaners are examples of highly alkaline substances that rapidly give up OH− ions, thereby raising the pH. A familiar household item that is very alkaline is drain cleaner. Other common alkaline substances include bleach and ammonia. Alkaline cleaning agents often contain additional compounds, such as dispersants and chelants, to enhance cleaning efficiency.
Some examples of weak bases are seawater, which has a pH near 8.0, and baking soda. It's significant to note that extremely alkaline conditions can also be harmful to life, just as very acidic conditions can be harmful. Alkaliphiles are organisms capable of thriving at high pH levels, even around the pH of household bleach.
Furthermore, alkaline cleaners are known to dissolve fats, oils, and proteins, which is why they are commonly used to clean areas contaminated with these substances. Indicator substances like litmus paper and phenolphthalein are used to identify alkaline solutions, with bases turning red litmus paper blue and phenolphthalein turning pink.