0
1. (d) 10

2. (b) HCl

3. (d) 16 mL

4. (c) antacid

5. (a) Zinc + Sulphuric acid Zinc sulphate +Hydrogen
 Zn + H2SO4 ZnSO4 + H2
(b) Magnesium + Sulphuric acid magnesium chloride +Hydrogen gas
 Mg + HCl MgCl2 +H2
(C) Aluminum + Sulphuric acid Aluminum sulphate +Hydrogen gas
 Al + H2S04 Al2 (S04)3 + H2
 (d) Iron + Hydrochloric acid Iron chloride +Hydrogen
 Fe + 2HCl FeCl2 + H2

6. Alcohol and glucose both contain hydrogen but not categorized as acids. This can be
proved by following activity.
Material required: - Beaker, nails, battery, connecting wires, bulb, switch and
alcohols.

Procedure:
1. Set up the experiment as follows
2. Take ethyl alcohol in the beaker in the beaker.
3. When the switch is turned on, the bulb does not glow.
4. Take glucose solution in place of alcohols but bulb does not glow.
  
7. Rain water contains small amount of acid because of which it conducts electricity.
Distilled water is pure water. It does not contain ions. Therefore, it does not conduct
electricity.

8. Acids produce hydrogen ions or hydronium ions only in presence of water.
Therefore, it shows acidic behavior only presence of water.

9. (a) D (b) C
 (c) B (d) A
 (e) E Material downloaded from http://myCBSEguide.com and http://onlineteachers.co.in
Portal for CBSE Notes, Test Papers, Sample Papers, Tips and Tricks

10. HCl is stronger acid than CH3COOH. Therefore, H+ ions concentration in test tube A
will be more than that in test tube B. hence, reaction will take place faster in test
tube A than in test tube B. so, fizzing will occur more vigorously in test tube B.

11. Bacteria change the fresh milk into curd by producing lactic acid. Because of the
presence of lactic acid in curd, the pH will come down from 6 to lower value.

12. (a) The pH of milk changes from 6 to slightly alkaline on addition of a very small
amount of baking soda. This is because sodium hydrogen carbonate (baking soda) is
basic in nature. This prevents the milk from souring.
 (b) Lactic acid formed as a result of fermentation is neutralized by sodium hydrogen
carbonate. This prolongs the time taken by milk to set as curd.

13. Plaster of Paris reacts with moisture to form gypsum and sets to a hard mass.
Therefore, it should be stored in moisture-proof container.

14. The reaction between an acid and a base to give salt and water is called
neutralization reaction.
 For example:
 NaOH + HCl - NaCl + H2O
 KOH + HNO3 K NO3 + H2O

15. Uses of washing soda:
 (i) As cleansing agent.
 (ii) Removing permanent hardness of water.
 (iii) Used in glass, soap and paper industries.
 Uses of baking soda:
(i) For making baking powder.

(ii) As ingredient of antacid. 

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