Indian School Al Wadi Al Kabir

INDIAN SCHOOL AL WADI AL KABIR

DEPARTMENT OF SCIENCE

CLASS X CHEMISTRY DATE:

W.S. No.2 Topic: Acids, Bases and Salts Name:

Answer the following in one word or one sentence. Each question carries 1 mark

1. Two solutions A and B have pH values 3 and 8 respectively. Which solution will be basic in nature?

2. Which gas is evolved when the sodium bicarbonate solution is added to Tartaric acid?

3. Fresh milk has pH of 6. When it changes into curd, will its pH increase or decrease? Why?

[Hint: Formation of curd increases the amount of lactic acid]

4. How is Plaster of Paris obtained? What reaction is involved in the setting of a paste of Plaster of Paris?

5. What would-be be the color of the red litmus solution in sodium carbonate solution?

Answer the following in about 30 words. Each question carries 2 marks.

6. Why does a bee sting cause irritation and pain? What is the common remedy to overcome the pain?

7. Tooth enamel is the hardest substance in our body. How does it undergo damage due to eating chocolates and sweets? How do tooth pastes prevent this damage? [VBQ]

8. A truck carrying concentrated Nitric acid overturns and spills its contents. The acid

drains into a nearby pond. The pH of pond water was 8 before spill and it becomes 5 after a spill. Name an ion in the pond water that has increased its concentration after the spill. What colour would Methyl orange be at the new pH?

9. What happens when Chlorine is passed over slaked lime at 313 K? Write chemical equation for the reaction involved and state two uses of the product obtained. Answer the following question in 50 words each.Each questions carry 3marks each.

10. A compound X of Sodium forms a white powder. It is a constituent of baking powder and is used in some antacid preparations. When heated X gives out a gas and steam. The gas forms a white precipitate with lime water. Write the chemical formula and name of X and the chemical equations for its decomposition on heating.

11. Name the constituents of baking powder. What is the function of each constituent of baking powder in the manufacture of cake? (2010 SA I)

12. An apparatus was set up as shown in the diagram. It was observed that when an aqueous solution of HCl was taken in the beaker and the circuit was closed, the bulb in the circuit began to glow, but it did not glow when the experiment was repeated with glucose solution. What could be the reason?

Would the bulb glow if the same experiment is repeated with an aqueous solution

(i) NaOH (ii) NaCl? Why? (2010 SA I)

13. A few crystals of copper sulphate are heated in a dry boiling tube.

(a) State their colour before and after heating.

(b) Give the reason for this colour change

(c) How can the original colour be restored?

(d) Write the chemical formula of the copper sulphate so obtained. (2012 SA 1)

14. What is meant by water of crystallization? How many molecules of water are present in hydrated copper sulphate.Write its formula.What colour change do you observe when its heated? (2012 SA 1 ISG )

15. Identify the Calcium compound which is used for plastering fractured bones. With the help of a chemical equation, describe how this compound is prepared. What special precautions should be taken during the preparation of this compound? Answer the following questions in about 70 words.The questions carry 5 marks

16. The preparation of hydrogen gas is shown in the given figure. What would happen if the following changes are made?

(a) Instead of dilute sulphuric acid, dilute hydrochloric acid is taken

(b) In place of Zinc, copper turnings are taken

(c) Sodium hydroxide is taken in place of dilute sulphuric acid and the tube is heated

[HOTS]