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प्रश्न
State of the following formula of a compound is incorrect. Incorrectly write the correct formula.
KNO3
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उत्तर
KNO3 is the correct formula.
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संबंधित प्रश्न
Write down the formulae of sodium sulphide.
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Name the elements water is made of. What are the valencies of these elements ? Work out the chemical
formula for water.
If the valency of carbon is 4 and that of sulphur is 2, work out the formula of the compound formed by the combination of carbon with sulphur. What is the name of this compound ?
An element Y has a valency of 4. Write the formula for its :
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- oxide
- sulphate
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Complete the following statement by selecting the correct option :
The correct formula of aluminium oxide is
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Write the formula of the following compound:
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Lead [II] nitrate
Write the formula of the following compound:
Lead [II] sulphate
Give the chemical formulae for the following compounds and compute the ratio by mass of the combining elements in each one of them. (You may use appendix-III).
- Ammonia
- Carbon monoxide
- (Hydrogen chloride
- Aluminium fluoride
- Magnesium sulphide
Complete the following crossword puzzle (Fig. 3.1) by using the name of the chemical elements. Use the data given in Table.
| Across | Down | ||
| 2 | The element used by Rutherford during his α–scattering experiment | 1 | A white lustrous metal used for making ornaments and which tends to get tarnished black in the presence of moist air |
| 3 | An element which forms rust on exposure to moist air | 4 | Both brass and bronze are alloys of the element |
| 5 | A very reactive non–metal stored under water | 6 | The metal which exists in the liquid state at room temperature |
| 6 | Zinc metal when treated with dilute hydrochloric acid produces a gas of this element which when tested with burning splinter produces a pop sound. | 8 | An element with symbol Pb |
Play a game for writing formula.
Example 2: A low-cost model for writing formulae: Take empty blister packs of medicines. Cut them in groups according to the valency of the element, as shown in the figure. Now, you can make formulae by fixing one type of ion into other.
For example:
The formula for sodium sulphate:
2 sodium ions can be fixed on one sulphate ion.
Hence, the formula will be Na2SO4.
Do it yourself:
Now, write the formula of sodium phosphate.
