A base is a substance that feels:
a) Rough b) Smooth c) Slimy d) Soapy e) Hot
The correct answer and explanation is:
The correct answer is (c) Slimy.
Bases are substances that tend to feel slippery or slimy when touched. This sensation arises due to their ability to react with the natural oils and fats present on the skin. Bases, also known as alkaline substances, have a pH greater than 7. They can accept protons (H+) or donate electron pairs. When bases dissolve in water, they release hydroxide ions (OH−). These hydroxide ions interact with the oils on your skin, forming soap-like compounds, which is why they feel slimy or slippery.
Common examples of bases include substances like soap, baking soda, and ammonia. When these substances come into contact with water, they can easily break down oils and fats, producing a smooth, slippery feeling. This is why soap, which is a basic substance, makes washing your hands feel so slippery.
In contrast, acidic substances, which have a pH of less than 7, tend to feel more irritating or rough on the skin. Acidic substances like lemon juice or vinegar do not interact in the same way with oils and fats and can sometimes cause a stinging or burning sensation if left on the skin for too long.
This characteristic of bases to feel slimy is not only useful in daily life, like when using soap, but it also plays a role in various chemical processes, including cleaning, where bases break down dirt and grease through the reaction with fats and oils.
In summary, bases feel slimy because of their ability to form soap-like compounds that react with oils and fats on your skin, producing a slippery sensation.