Q20 of 270 Page 79

(a) What is a universal indicator? For what purpose is it used?

(a) Universal indicator is a mixture of several indicators. It shows different colours at different concentrations of hydrogen ions in a solution. It is used to measure the pH.

More from this chapter

All 270 →
18 Fill in the following blanks with suitable words:

(a) Acids have a pH.................than 7.


(b) Alkalis have a pH.............. than 7.


(c) Neutral substances have a pH of ...............


(d) The more acidic a solution, the ................... the pH.


(e) The more alkaline a solution, the.................... the pH.

 19 Fresh milk has a pH of 6. When it changes into curd (yogurt), will its pH value increase or decrease? Why? 20 How does a universal indicator work? 20 Water is a neutral substance. What colour will you get when you add a few drops of universal indicator to a test-tube containing water?