What is a Base?
Chemists refer to a proton accepting molecule and ion as a base. Thus OH- is a base. They keep the term “alkali” for bases dissolved in water. So for instance sodium hydroxide NaOH dissolves in water, separating into Na+ ions and OH– ions. It is therefore a source of the base OH– and the solution is an alkali.
General Properties of Bases
- Bases release a hydroxide ion (OH–) into water. The more ions that are released the stronger the base.
- Bases react with acids. When an acid and a base react, they form water and a substance called a salt.
- Bases turn red litmus blue.
Bases can change the structure of a protein. This property of base is what makes bases feel slippery. Soap is a base that, when it gets wet, feels very slippery on your skin. This same property to change the structure of proteins makes some strong bases very dangerous.
Strong bases that will dissolve in water, such as lye, are extremely dangerous, because human skin has many proteins in it. When these strong bases come in contact with skin., they begin to change the structure of the skin. This can cause burns. Strong bases need to be used very carefully to avoid damage to skin.
Physical Properties of Bases
- Bases taste bitter – There are very few food materials that are alkaline. It is even more important that care be taken in tasting bases. Tasting of bases is more dangerous than tasting acids because of the property of stronger bases to denturate protein.
- Bases release a hydroxide ion in water solution.
- Bases neutralise acids in a neutralization reaction – The word reaction means that an acid plus a base makes water plus a salt. Symbolically where “Y” is the anion of acid “HY”. ‘X’ is the cation of base ‘XOH’ and ‘XY” is the salt in the product, the reaction is
HY + XOH → HOH + XY
- Bases denature protein – This accounts for the slippery feeling on the hands when exposed to a base. Strong bases that dissolve in water well, such as sodium or potassium lye, are very dangerous because a great amount of the structural material of human beings is made of protein. Serious damage to flesh can be avoided by careful use of strong bases.
- Bases turn red litmus to blue – This is not to say that litmus is the only acid base indicator, but that it is likely the oldest one.
Frequently Asked Questions on Properties of Bases
Is density a physical or chemical property?
A physical property is an attribute of a substance that is visible or measurable without altering the substance ‘s identity. The physical properties include points of colour, density, hardness and melting and boiling. A chemical property defines a substance’s ability to undergo one specific chemical transition.
What’s a chemical property example?
Examples of chemical properties include flammability, toxicity, acidity, reactivity (various types), and combustion heat. For example, iron combines with oxygen to form rust in the presence of water; chromium does not oxidise.
What are bases used for?
We use bases at home as cleaning agents, and as antacid medicines. Popular examples of homemade bases include soaps; lye, for example, used in oven cleaners; magnesia milk; and Tums. Each one has a pH of more than seven, has the ability to consume free hydrogen, and can neutralize acids.
How do you identify a base?
To decide if a substance is an acid or a base, before and after the reaction, count the hydrogens on each substance. When the number of hydrogens decreases this product is the acid (donates ions of hydrogen). When the amount of hydrogen has risen this material is the basis (accepts ions of hydrogen).
What are the two types of bases?
The number of ionizable hydroxide ( OH–) ions present in one base molecule is called baseline acidity. Based on acidity bases, three forms can be classified: mono acidic, diacidic, and triacidic.