| 1. | Which of the following is used for dissolution of gold ? | |
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Aqua- regia
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Sulphuric acid
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Hydrochloride acid
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Nitric acid
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Report Question| 2. | Which of the following statement is or are incorrect ? | |
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The acids prepared from the minerals of the earth are called mineral acids.
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Concentrated mineral acids are weak acids, so they are not very dangerous.
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Organic acids are weak acids, so it is not harmful to eat or drink.
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The acids present in plants materials and animals are called organic acids.
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| 3. | Which of the following statement is or are incorrect ? | |
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The acids prepared from the minerals of the earth are called mineral acids.
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Concentrated mineral acids are weak acids, so they are not very dangerous.
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Organic acids are weak acids, so it is not harmful to eat or drink.
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The acids present in plants materials and animals are called organic acids.
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| 4. | Calcium phosphate is present in tooth enamel. its nature is ? | |
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Neutral
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Amphoteric
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Basic
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Acidic
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| 5. | Tooth enamel is made up of ? | |
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potassium
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calcium phosphate
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calcium oxide
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calcium carbonate
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| 6. | The PH of a solution of HCL is 4. This shows that the molarity of the solution is ? | |
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0.001M
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0.0001M
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4.0M
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0.4M
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| 7. | Chemical formula of washing soda is ? | |
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Na2C03 . 2H2O
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Na2C03 . 10H2O
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Na2C03 . 5H2O
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Na2C03 . 7H2O
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| 8. | At what temperature is gypsum heated to form Plaster of Paris ? | |
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120°C
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110°C
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100°C
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90°C
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| 9. | When hydrogen chloride gas is prepared on a humid day, the gas is usually passed through the guard tube containing calcium chloride. The role of calcium chloride taken in the guard tube is to ? | |
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absorb moisture from the gas
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moisten the gas
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absorb Cl– ions from the evolved gas
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absorb the evolved gas
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| 10. | An indicator is one kind of the following compound ? | |
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Complex salt
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Weak base or acid only
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Reducing agent
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Strong acid only
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