Be reactive. Q What is an indicator? A: A substance that changes colour depending upon whether it is acidic, neutral or alkaline solution. Q What is litmus? A: Litmus is an indicator made from lichen plant which turns red in acid an d blue in alkaline solutions.
Q What is universal indicator?A: Universal indicator is a mixture of four different indicators. It has range of colours like rainbow. It shows how strong or weak the acid or alkali is. It comes in the form of paper or a solution.
Q What is pH value?A: The degree of acidity or alkalinity of a substance can be expressed by its pH value. Acids have pH value of less than 7. Alkalis have pH value of more than 7. Neutral solutions have a pH of 7.
Q What is pH Meter and pH Sensor? How it is used?A: pH meter and pH Sensor are used to get accurate pH values. In pH Meter, the electrode is simply dipped into a solution and pH value is read from the meter. A pH sensor can also be connected to a computer and the pH values are read from the screen.
Q Give pH value of different parts in our body.A: The human body contains lots of liquids which have different pH value. Ex Liquid in stomach have 1.5 pH, because they contain hydrochloric acid. Saliva has 6.2, blood has 6.5, intestinal juice has 8.4 and our skin has 5.5 pH values.
Q How is pH value of soil important for farmers?A: Different plant grows in different soil. For apple trees pH value should be 5 to 6 (slightly acidic) and for mint plants 7 to 8 (neutral or slightly alkaline). If soil is too acidic then farmers can add lime (an alkali) to neutralise the soil.