NCERT Class 10 Science Acids Bases and Salts

CHAPTER-2

Acids, Bases and Salts

2.1 UNDERSTANDING THE CHEMICAL PROPERTIES OF ACIDS AND BASES

2.1.1 Acids and Bases in the Laboratory

These indicators tell us whether a substance is acidic or basic by change in colour. There are some substances whose odour changes in acidic or basic media. These are called olfactory indicators. Let us try out some of these indicators.Which of these – vanilla, onion and clove, can be used as olfactory indicators on the basis of your observations? Let us do some more activities to understand the chemical properties of acids and bases. The bulb will start glowing in the case of acids, as shown in Fig. 2.3. But you will observe that glucose and alcohol solutions do not conduct electricity. Glowing of the bulb indicates that there is a flow of electric current through the solution. The electric current is carried through thesolution by ions.

Since the cation present in acids is H+, this suggests that acids produce hydrogen ions, H+(aq), in solution, which are responsible for their acidic properties. Repeat the same Activity using alkalis such as sodium hydroxide, calcium hydroxide, etc. What can you conclude from the results of this Activity?

QUESTION

1. What is the common name of the compound CaOCl2?

2. Name the substance which on treatment with chlorine yields bleaching powder.

3. Name the sodium compound which is used for softening hard water.

4. What will happen if a solution of sodium hydrocarbonate is heated? Give the equation of the reaction involved.

5. Write an equation to show the reaction between Plaster of Paris and water.

Please refer to attached file for NCERT Class 10 Science Acids, Bases and Salts