The most commonly used natural indicator is litmus. It is extracted from lichens . It has a mauve (purple) colour in distilled water. When added to an acidic solution, it turns red and when added to a basic solution, it turns blue. It is available in the form of a solution, or in the form …
Special type of substances are used to test whether a substance is acidic or basic. These substances are known asindicators. The indicators change their colour when added to a solution containing an acidic or a basic substance. Turmeric, litmus, China rose petals (Gudhal), etc., are some of the naturally occurring indicators.
Name of acid Found inAcetic acid VinegarFormic acid Ant’s stingCitric acid Citrus fruits such as oranges, lemons, etc.Lactic acid CurdOxalic acid SpinachAscorbic acid Amla, Citrus fruits (Vitamin C)Tartaric acid Tamarind, grapes, unripe mangoes, etc.All the acids mentioned above occur in nature Name of base Found inCalcium hydroxide Lime waterAmmonium hydroxide Window cleanerSodium hydroxide/ SoapPotassium hydroxideMagnesium …
substances like these which are bitter in taste and feel soapy on touching are known as bases.The nature of such substances is said to be basic. eg soap, baking soda
These substances taste sour because they contain acids. The chemical nature of such substances is acidic. The word acid comes from the Latin word acere which means sour. The acids in these substances are natural acids.
The heat flows from a body at a higher temperature to a body at a lower temperature. There are three ways in which heat can flow from one object to another. These are conduction, convection and radiation.
Dark-coloured objects absorb more heat than the light-coloured objects. That is the reason we feel more comfortable in light-coloured clothes in the summer.
Woollen clothes keep us warm during winter. It is so because wool is a poor conductor of heat and it has air trapped in between the fibres.
From the sun the heat comes to us by this process is known as radiation. The transfer of heat by radiation does not require any medium. It can take place whether a medium is present or not. A hot utensil kept away from the flame cools down as it transfers heat to the surroundings by …
At night it is exactly the reverse. The water cools down more slowly than the land. So, the cool air from the land moves towards the sea. This is called the land breeze.
