ASSIGNMENT : FIRST TERM (2012-2013)SUBJECT: CHEMISTRY:CHAPTER: METALS AND NON- METALS
| ASSIGNMENT : FIRST TERM (2012-2013) X - CHEMISTRY CHAPTER: ACIDS AND BASES Max Marks: 25 |
| A. Very short answer questions: (1 mark each) (1x 6= 6marks) |
| 1. A calcium compound which is yellowish white powder is used as a disinfectant and also in textile industry. Name the compound. Which gas is released when this compound is left exposed to air ? |
| 2. Which element is common to all acids ? |
| 3. What is common name of water soluble bases ? |
| 4. Write the neutralization reaction between acids and bases in terms of the ions involved. |
| 5. Two solutions A and B have pH values 3.0 and 9.5 respectively. Which of these will turn litmus solution from blue to red and which will turn phenolphthalein from colourless to pink. |
| 6. Name the raw material used for the production of caustic soda. |
| B. Short answer questions: (2 marks each) (2x5=10) |
| 1. State the chemical property in each case on which the following uses of baking soda are based: |
| a. as an antacid |
| b. as a constituent of baking powder |
| 2. Take 5 ml of hydrochloric acid in boiling tube or a conical flask. Add few pieces of zinc granules to it. |
| a. What do you observe on the surface of zinc granules? |
| b. Name the gas evolved. |
| c. What happens when the above gas is passed through soap solution ? |
| d. What happens when a burning candle is brought near the gas filled bubble ? |
| 3. A housewife found that the cake prepared by her is hard and small in size. Which ingradient has she forgotten to add that would have made the cake fluffy. Give reason. |
| 4. Crystals of a substance changed their colour on heating in a closed vessel but regained it after sometime when allowed to cool down. Name one such substance. Explain the phenomenon involved. |
| 5. How is plaster of paris prepared ? Write the equation of the reaction involved. |
| C. Short answer questions: (3 marks each)(3x 3= 9) |
| 1. A compound X of sodium forms a white powder. It is a constituent of baking powder and is used in some antacid prescriptions. 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 equation for its decomposition on heating. What is its role in baking powder and in antacids. |
| 2. What is the role of pH in our daily life ? |
| 3. What happens when: |
| (a) solid sodium hydrogen carbonate is heated |
| (b) chlorine gas is passed through dry slaked lime |
| (C) gypsum is heated to a temperature of 373 K. |
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