InterviewSolution
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InterviewSolution
This section includes InterviewSolutions, each offering curated multiple-choice questions to sharpen your knowledge and support exam preparation. Choose a topic below to get started.
| 1. |
Which of the following reactions is a synthesis reaction?A. When steam is passed over red hot coke, a mixture of carbon monoxide and hydrogen 15 fomed .B. Sodium reacts with water co form sodium hydroxide and hydrogen .C. When the milk of lime (calcium hydroxide) is added to hot sodium carbonate solution, sodium hydroxide is obtained and calcium carbonate separates out as mud.D. Stannic chloride is perpared by passing chlorine into molten tin. |
| Answer» Correct Answer - C::D | |
| 2. |
`Pb(NO_3)_2+Fe_2(SO_4)_3toFe(NO_3)_3+PbSO_4` Coefficients of lead sulphate and ferric nitrate in the balanced equation of above reaction areA. 3,4B. 3,3C. 3,2D. 2,3 |
| Answer» Correct Answer - C | |
| 3. |
Sugar, on being treated with `H_2SO_4`, forms a black residue. If we observe the weights of sugar and the residue, we find a difference m weights. Why? |
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Answer» (i) Sugar undergoes chemical change. (ii) Dlack carbon residue is formed. (iii) Sugar is a combination of carbon, hydrogen and oxygen. |
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| 4. |
Why is a physical change reversible? |
| Answer» No change in molecular composition | |
| 5. |
Why is the action of heat on iodine a physical change? |
| Answer» Sublimation, no change in molecular composition | |
| 6. |
Why is the burning of LPG a chemical change? |
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Answer» (i) Composition of LPG (ii) Products obtJincd on combustion |
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| 7. |
The valency of a metal is 2 and its atomic weight is 24. What will be the molecular weight of its (a) sulphite (b) chloride (c ) chloride? |
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Answer» (I) Formula of salts bsed on valency of metal. (ii) Derivation of formulae of the compounds based on the valency of the metal. (iii) Significance of corresponding molecular weight. |
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| 8. |
Classify the following into physical and chemical changes. (i) Freezing of water (ii) Fermentation of alcohol (iii) Burning of coal (iv) Breaking of glass (v) Glowing of an electric bulb |
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Answer» (i) Change in composition (ii) New products formation. |
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| 9. |
The valency of nitride ion is same as the valency of __________ ionA. FerricB. plumbicC. zincD. calcium |
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Answer» Correct Answer - A Nitride : `N^(3-)` Ferric : `Fe^(3+)` Whereas others are `Pb^(+4),Zn^(+2),Ca^(+2)` |
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| 10. |
Blue coloured `CuSO_4` is taken in two test tubes A and B. Zinc granules are added to test tube A and small iron piecces are added to test tube B. Explain the observations in each acse by giving reasons. |
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Answer» (i) Reactivity series of metals. (ii) Reactivity of metals according to metal reactivity series. (iii) Reactions taking place. (iv) Change in property of the solution due to the reaction. |
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| 11. |
A hydrocarbon on complete combustion produces 176 g of carbon dioxide and 90 g of water. What will x the formula of hydrocarbon be and also give balanced chemical equation of combustion of hydrocarbon? |
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Answer» (i) General balanced chemical equation for combustion of hydrocarbon. (ii) Calculation of the coefficients of carbon dioxide and water using the formula (iii) Coefficient of `CO_2=("Amount of "H_2O" produced")/("Molecular weight ")` (iv) Coefficient of `H_2O=("Amount of "H_2O" produced")/("Molecular weight ")` (v) Chemical formula of hydrocarbon from the coefficients of corbon dioxide and water |
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| 12. |
Why do chemical reactions involve loss or gain of energy? |
| Answer» Energy changes during making or breaking of bonds. | |
| 13. |
Define cxotherrnic reaction. Give an example. |
| Answer» Release of heat energy | |
| 14. |
`Ag+CuSO_4toCu+AgSO_4` Is this reaction possible ? Explain. |
| Answer» Cu is more electropositive than Ag | |