Acids Bases and Salts

Acids and bases affect chemistry and our day to day life as well. They can be identified by their taste; acids taste sour and bases taste bitte. Acids are found in many substances including food items but their presence in fruits is very prominent, e.g., citric acid is present in citrus fruits such as orange and lemon. Vinegar contains acetic acid. Apart from these, some acids are widely used in the laboratory, like hydrochloric acid, sulfuric acid and nitric acid.

The bases which are soluble in water are called alkalis. In general, bases are found in household cleaners to clean grease from windows and floors and also in soaps, toothpastes, egg whites, dish washing liquids and household ammonia.

Our body contains some very common acids like dilute hydrochloric acid in the stomach, which causes indigestion of food. If the contents of our stomach become too acidic, we get indigestion and a burning sensation in the stomach. Acids and bases also regulate metabolic activities in the human body through equilibrium processes. Bee stings are acidic in nature while wasp stings are alkaline in nature.

All acids generate hydrogen gas on reaction with metals. Hydrogen is common to all acids. In fact

• Acids, bases and salts are three main categories of chemical compounds. They have certain definite properties which distinguish one class from the other. 
• The sour taste of many fruits and vegetables, lemon for instance, is due to various types of acids present in them. 
• The digestive fluids of most animals and humans also contain acids. The word 'acid' is derived from a Latin word, which means "sour". 
• The acids we use in the laboratory are very strong acids like hydrochloric acid and sulfuric acid. Strong acids are corrosive and can burn your skin. 
• Bases, on the other hand, are the chemical opposite of acids. They are bitter in taste and soapy to touch. 
• Sea water and detergents are some examples of substances that are basic. Many bases are oxide or hydroxide compounds of metals. 
• Strong bases can also burn one's skin. Tasting a substance is not the right way of finding out if it is an acid or a base! Acids and bases can be better distinguished with the help of indicators. 
• Indicators are substances that undergo a change of color with a change of acidic, neutral or basic medium. 
• Litmus, a purple dye extracted from the lichen plant, is commonly used as an indicator in laboratories. 
• Acids change the color of litmus solution to red, and bases change the color of litmus solution to blue. Turmeric is another common household indicator. 
• A stain of turmeric based food spill on a white cloth becomes reddish-brown when soap is scrubbed on it. 
• Soap is basic in nature and changes the color of the turmeric stain. It turns yellow again when the cloth is washed with plenty of water.