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प्रश्न
lt was Paheli’s birthday. Her grandmother gave her two gifts made of metals, one old dull silver spoon and a pair of lustrous gold earrings. She was surprised to see the difference in the appearance of the two metals. Can you explain the reason for this difference?
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उत्तर
Gold is a noble metal it does not react with the gases present in the atmosphere. Silver reacts with some gases like hydrogen sulphide and loses its shine in moist air.
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संबंधित प्रश्न
Match the objects that are made of the same material.
| A | B | C |
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 |
 |
 |
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 |
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Sort the given objects as rough or smooth.
| Wet soap | Coir | Feather | Stone |
| ______ | ______ | ______ | ______ |
| Glass ball | Paperboard | Sand paper | Plastic spoon |
| ______ | ______ | ______ | ______ |
Sand settles down in the water.
Some of the following statements are incorrect. Find the incorrect statements and correct them.
- The property of metals by virtue of which they can be drawn into wires is called ductility.
- Metals are good conductors of electricity but poor conductor of heat.
- Articles made up of metals produce ringing sound when struck hard.
- Oxides of non-metals and metals are acidic in nature.
- A less reactive metal displaces a more reactive metal from its salt solution in water.
Fill in the blanks to complete the following paragraph.
The name of the product formed in the reaction of sulphur and ______ is sulphur dioxide gas. When sulphur dioxide is dissolved in ______, sulphurous acid is formed. The sulphurous acid turns ______ litmus paper to ______. Generally oxides of ______ are acidic in nature.
After completing the paragraph, write two questions which you can raise on the basis of this information.
While doing an activity in class, the teacher asked Paheli to handover a transluscent material. Which among the following materials will Paheli pick and give her teacher?
Which pair of substances among the following would float in a tumbler half filled with water?
Match the objects given in Column I with the materials given in Column II.
| COLUMN I | COLUMN II | ||
| (a) | Surgical instruments | (i) | Plastic |
| (b) | Newspaper | (ii) | Animal product |
| (c) | Electrical switches | (iii) | Steel |
| (d) | Wool | (iv) | Plant product |
Differentiate among opaque, translucent and transparent materials, giving one example of each.
Sugar, salt, mustard oil, sand, sawdust, honey, chalk powder, petals of flower, soil, copper sulphate crystals, glucose, wheat flour are some substances given to Paheli. She wants to know whether these substances are soluble in water or not. Help her in identifying soluble and insoluble substances in water.
