| 1. | The reaction of H2 gas with oxygen gas to form water is an example of ? | |
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exothermic reaction
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all of these reactions
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combination reaction
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redox reaction
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Report Question| 2. | Which of the following is a physical change ? | |
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Getting salt from sea water
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Burning of wood
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Formation of curd from milk
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Ripening of fruits
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| 3. | Give the ratio in which hydrogen and oxygen are present in water by volume ? | |
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1:8
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1:2
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1:1
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2:1
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| 4. | Which Of The Following Processes Involve Chemical Reactions ? | |
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Liquefaction of air
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Heating copper wire in the absence of air at high temperature
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A storing of oxygen gas under pressure in a gas cylinder
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Keeping petrol in china dish in an open
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| 5. | The condition produced by aerial oxidation of fats and oils in foods marked by unpleasant smell and taste is called ? | |
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Corrosion
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Rancidity
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Reduction
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Antioxidation
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| 6. | A substance added to food containing fats and oils is called ? | |
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Antioxidant
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Oxidant
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Rancid
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Coolant
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| 7. | The process of reduction involves ? | |
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removal of hydrogen
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removal of oxygen
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addition of hydrogen
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addition of oxygen
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| 8. | The reaction in which two compounds exchange their ions to form two new compounds is ? | |
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a double displacement reaction
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a displacement reaction
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an isomerization reaction
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a decomposition reaction
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| 9. | Which Of The Following Is Not A Physical Change ? | |
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Dissolution of salt in water
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Combustion of Liquefied Petroleum Gas (LPG)
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Boiling of water to give water vapour
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Melting of ice to give water
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| 10. | When green coloured ferrous sulphate crystals are heated, the colour of the crystal changes because ? | |
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it loses water of crystallisation
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it forms SO3
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it is decomposed to ferric oxide
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it forms SO2
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