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. |
Analyse the above diagrams and answer the following questions. (a) Identify the test tube (s) in which new substance (s) is`//`are formed. (b) Does the composition change in all the test tubes ? Give reasons . (C ) Identify the colour changes associated with the relevant physical change given. |
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Answer» (a) heating of mercuric oxide is a chemical change. Hence in test tube -C new substance is formed (b) Heating of wax and zinc oxide are physical changes Hence in test -A test tube-B the molecular composition remains the same (C ) In test tube-B change in colour is observed. Zinc oxide is white in colour and turns to yellow on heating |
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| 2. |
Match the following |
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Answer» Correct Answer - `(A) to ( C) :(B) to (f) ;( C) to (a) (D) to (b) : (E ) to (d); (F) to ( e)` `(A) to ( C),(B) to (f), (C ) to (a)` `(D) to (b) ,(E ) to (d), (F) to (e )` |
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| 3. |
Match the following |
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Answer» Correct Answer - `(A) -(b) -(iii) ; (B) -( C) -(iv) ; (c ) -(d) -(v) ;(D) -(e ) -(ii) ; (E ) -(a) -(i)` `(A) to (b) to (iii) ,(B) to (C ) to (iv),` `( C) to (d) to (v) , (D) to (e ) to (ii) ,` `(E ) to (a) to (i)` |
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| 4. |
Give two example for the followingA. fast changesB. Desirable changesC. non- periodic changesD. Physical changes |
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Answer» (a) Burning of a match stick glowing of an electric bulb. (b) formation of curd from milk , formation of manure. (C ) Sneezing rusting of iron. (D) Melting of ice, evaporation of water. (e ) Germination of seeds , cooking of food . |
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| 5. |
Which among the following molecules possesses the maximum number of oxygen atoms?A. Carbon dioxideB. Nitric acidC. Sulphuric acidD. Calcium oxide |
| Answer» Correct Answer - C | |
| 6. |
What type of change is formation of coal ? A. `A-e,B-d,C-a,D-c,E-b`B. `A-c,B-d,C-e,D-b,E-a`C. `A-b,B-e,C-a,D-c,E-d`D. `A-c,B-d,C-b,D-e,E-a` |
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Answer» Correct Answer - C Formation of coal is a desirable slow nonperiodic and irreversible change. Hence ,the correct option is (C ) |
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| 7. |
Identify the incorrect formulae among the following : (A) `CaO_(2)` (B) `Na_(2)O` (C ) `Mg_(3)S_(2)` (D) `Mg_(2)O`A. A,B,DB. A,C,DC. C,D,ED. B,C,D |
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Answer» Correct Answer - B Incorrect formulae are `CaO_(2) ,Mg_(3) S_(2),Mg_(2)O` Hence the correct option is (b) |
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| 8. |
A desirable change is always associated with an undesirable change. Give as example. |
| Answer» Spraying chemical on vegetables and fruits to kill insects is a desirable change for the farmer but it is an undesirable change for people who consume them. | |
| 9. |
The formula of a compound of a metal with oxygen is written as MO and that of another metal is written as `M_(2)O` .Give reason. What are the formulae of the compounds of the above metals with chlorine ? |
| Answer» In case of a metal having combing capacity 2 the formula of its compound with oxygen is written as MO since the combing capacity of oxygen is also 2. In case of a metal having combing capacity 1, the formula of the compound is written as `M_(2)O`. Since the combining capacity of chlorine is 1, the formulae of the compounds of chlorine with the above metals are `MCI_(2) " and " MCI` respectively. | |
| 10. |
Burining of cracker is a `"______"` and `"______"` changeA. physical ,fastB. chemical , fastC. chemical ,slowD. physical, slow |
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Answer» Correct Answer - B Burning of cracker is a fast and chemical change Hence , the correct option is (B) |
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| 11. |
Write the formulae of compounds with the following information and the names of the molecules.A. 2 phosphorus atoms 5 oxygen atoms.B. 1 calcium atom 2 oxygen atoms 2 hydrogen atoms.C. 1 iron atom ,1 sulphur atom, 4 oxygen atoms.D. 1potassium atom, 1 chlorine atom 3 oxygen atoms |
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Answer» (a) `P_(2)O_(4)rArr` Phosphorus pentoxide (b) `Ca(OH)_(2) rArr ` Calcium hydroxide (C ) `FeSO_(4) rArr ` Ferrous sulphate (d) `KCIO_(3) rArr` Potassium chlorate ( e) Na_(3)PO_(4) rArr ` Sodium phosphate |
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| 12. |
Write the formulae of different compounds formed among the given elements |
| Answer» The formulae of different compounds for the given elements are `CaO,CaS,Na_(2)O,Na_(2)O,Na_(2)S,Fe_(2)O_(3) Fe_(2),S_(3)` | |
| 13. |
Identify the incorrect formula among the following .A. `Mg_(2)O`B. `ZnO`C. `CaO`D. `SO_(3)` |
| Answer» Correct Answer - A | |
| 14. |
the smallest and ultimate particle of an element is called `"_____"` |
| Answer» Correct Answer - Atom | |
| 15. |
the symbol of manganese is `"_____"`A. MnB. MC. MaD. Mg |
| Answer» Correct Answer - A | |
| 16. |
Formula for hydrochloric acid is `"_____"` |
| Answer» Correct Answer - HCI | |
| 17. |
Define the followingA. Chemical changeB. Reversible changeC. Periodic changeD. physical change |
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Answer» (a) A chemical change is defined as a change in which the molecular composition of the substance changes and new substance are formed. (b) A change which can be reversed is called reversible change. (C ) A change which occurs again and agin after fixed intervals of time is called periodic change . (d) A physical change is defined as a change in which hte molecular composition of the substance remains unchanged nad no new substance |
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| 18. |
Swinging of clock pendulum is a `"_____"` change. |
| Answer» Correct Answer - PERIODIC | |
| 19. |
Give reasons for the following (a) When magnesium is burnt in air the weight of white ash obtained is more than magnesium metal. (b) The weight of rusted iron is more than that of the original metal. |
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Answer» (a) Magnesium on burning combines with oxygen to form magnesium oxide (white ash) .Hence the weight is found to be increased. (b) Since rusting is a chemical change a new substance is formed . In this change iron reacts with oxygen and moisture in the air to form iron oxide. Hence the weight of rusted iron is more then that of the original metal. |
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| 20. |
(a) Identify the products formed. (B) Observe the following figure and identify the change associated with it . ( C) Name the product formed in the following change |
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Answer» (a) Products `-CO_(2) " and " H_(2)O` (b) Rusting of iron (C ) Sugar charcoal (for) Carbon |
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| 21. |
Classify the following changes as reversible and irrefversible changes.A. Burning of candleB. Glowing of bulbC. Freezing of waterD. Curdling of milk |
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Answer» Reversible changes : Freezing of water ,glowing of bulb, magnetization of iron. Irreversible changes : Burning of candle ,curdling of milk burning of paper. |
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| 22. |
Classify the following into different changes.A. Making of dough from flourB. Digestion of foodC. Germination of seedsD. Burning of paper |
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Answer» (a) Show change , desirable change irreversible change non-periodic change and physical change. (B) Show change , desirable change irreversible ( C) Slow change desirable change irreversible non-periodic and chemical change. (d) Slow change desirable change irreversible non-periodic and chemical change. (e ) Fast change , irreversible ,non-periodic and chemical change. |
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| 23. |
Find the odd one out among the following sets give reasons.A. Nitrogen fluorine , oxygen , hydrogen , ozone.B. `CaO,NaCI,Co,FeS,KNO_(3)`C. `Se, K, Cu,Pb,SI`D. Bromine , iodine ,carbon ,sulphur, silicon |
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Answer» (a) Ozone (b) Co (C ) SI (d) Bromine (a) Ozone is a triatomic molecule while others are diatomic molecules . (b) Co is the symbol for cobalt which is an element while other are compounds. ( C) Sl is not the symbol for any element while others are symbols for the respective elements (d) Bromine is liquid non-metal and other are solids. |
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| 24. |
Analyse the observation of the above experiments |
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Answer» In case 1 evaporation of water takes place which is a physical change. In Case 2 sugar undergoes melting at the start which is a physical change.then sugar gets convertted to black-coloured substance called carbon which is a chemical change. |
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| 25. |
Study the diagrams and make a comment on the type of changes. |
| Answer» In the first case only the melting of wax takes place which is a physical change. In the second case ,the melting of wax is followed by burning of wax and so it involves both physical changes and chemical change respectively. | |
| 26. |
Identify the correct statements from the followingA. Symbol of copper is CoB. Silicon is a liquidC. The German name of tin is stannumD. Blue vitriol is `CuSO_(4).6H_(2)O` |
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Answer» (a) Symbol of copper is Cu. (b) Silicon is a solid. (C ) The Latin name of tin is stannum. (d) Blue vitrol is `CuSO_(4) . 5H_(2)O` (e ) Formula of magneseium sulphide is MgS. |
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| 27. |
Identify true or false statements among the following and rewrite the correct statements.A. An elements is made up of many kinds of atomsB. `3O_(2)` contains six atoms of oxygen.C. One molecule of calcium oxide contains three atoms,D. formula of nitrogen dioxide is `NO_(2)` |
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Answer» `"(a) False "" ""(b) True "" ""(c ) False"` `"(d) True "" ""(e ) False "` (a) An elements is made up of the same kind of atoms. (c ) One molecule of calcium oxide contains one oxygen atom and one calcium atom. (e ) In `Fe_(2)O` the combining power of iron is 3 and that of oxygen is 2. |
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| 28. |
Explain the type of changes involved in the above chart. |
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Answer» Case I : Melting of Ice `rArr` Physical change Case II : Addition of common salt to water : `rArr` Physical change Case III : Heating of salt solution involves evaporation. `rArr` Physical change Case IV : Rusting of iron nails `rArr` chemical change. |
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| 29. |
In which among the following changes does the molecular composition remain the same ? Justity. `|{:("(a) Photosynthesis",,"(b) Digestion of food"),("(C ) formation of clouds ",,"(d) Moulding of glass"),("(E )Melting of butter",,"(f) Perpiration "):}|` |
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Answer» In physical change composition remains the same . `( C ) , (d ) , (e ) ,(f )` are physical changes |
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| 30. |
Identify true or false statements among the followingA. Germinations is a fast change.B. Melting is an irreversible change.C. Water cycle involves chemical change.D. Beating of heart is a periodic change. |
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Answer» `"(a ) False "" ""(b) False "" ""(C )False"` `"(d) True "" ""(e )True"` |
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| 31. |
Classify the following into physical and chemical changes. (a) Expansion of metals on heating (b) Crystallization of salts from their solutions (C ) Blackening of silverware (d) Ripening of fruits (E ) Cooking of food (F) Melting of ice |
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Answer» `" (a) physical change "" ""(b) Physical change "` `" (C ) Chemical change "" ""(d) Chemical change "` `"(e ) Chemical change "" ""(f) Physical change "` |
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| 32. |
Study the diagram given below and answer the following questions. (a) Does the composition remain the same (b) Name the type of change involved . (c ) Write any two characteristics of the above change. |
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Answer» (a) Yes , composition remains the same. (b Physical change (c ) (i) In physical change new substances are formed. (ii) physical change is a temporary change. |
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| 33. |
Magnetization of iron is a `"_____"` change . (physical chemical irregersible). |
| Answer» Correct Answer - PHYSICAL | |
| 34. |
Rusting of iron is a `"_____"` change .(periodic , non- periodic , desirable) |
| Answer» Correct Answer - NON-PERODIC | |
| 35. |
Identify the physical and chemical changes among the followingA. Preparation of liquefied petroleum gasB. Usage of liquefied petroleum gasC. Formation of manureD. Formation of glass |
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Answer» (a) Physical change (b) Chemical change (c ) Chemical change (d) Chemical change (e ) Physical change |
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| 36. |
Are all chemical changes desirable changes ? Justify with at least five example. |
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Answer» All chemical changes are not dersirable Examples (1) Rusting of iron. (2) Spoilage of food. (3) Coagulation of milk (4) Blackening of silverware (5) Rancidification of oils These changes are not dersirable chemical changes as they result in wastage of resources. |
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| 37. |
Identify the test tube (s) in which a chemical changes takes place. (b) does the molecular composition remain the same in all the test tubes ? |
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Answer» (a) In test tube-c chemical change takes place Calcium oxide dissolves in water to form calcium hydroxide. This process is called slaking of lime and is applicable in white washing of buildings. (b) Addition of sugar or common salt to water is a physical change .the composition remains the same in test tubes A and B. |
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| 38. |
A change which can be reversed is called `"_____"` |
| Answer» Correct Answer - REVERSIBLE | |
| 39. |
Burining of coal is a `"_____"` change .(physical chemical ) |
| Answer» Correct Answer - CHEMICAL | |
| 40. |
Identify the chemical change among the followingA. Production of soundB. Magnetization of ironC.D. |
| Answer» Correct Answer - C | |
| 41. |
the Latin name of silver is `"_____"`A. AurumB. ArgentumC. StannumD. Plumbum |
| Answer» Correct Answer - B | |
| 42. |
Identify a true statement among the following.A. In a physical change composition changes.B. Chemical change can easily be reversec.C. physical change is a temporary changeD. In a chemical change no new substance (s) is`//` are formed. |
| Answer» Correct Answer - C | |
| 43. |
The burining of candle is a `"_____"` change.A. Perioic and irreversibleB. Reversible and chemicalC. Non-periodic and reversibleD. Chemical and irreversible |
| Answer» Correct Answer - D | |
| 44. |
Bursting of cracker is a `"_____"` and `"_____"` change,A. Chemical fastB. chemical slowC. physical fastD. physical slow |
| Answer» Correct Answer - A | |
| 45. |
Three atoms of chlorine are represented as `"_____"` |
| Answer» Correct Answer - 3CI | |
| 46. |
Atoms of `"_____"` (or ) `"_____"` can be regarded as molecules. |
| Answer» Correct Answer - noble gases (or ) inert gases | |
| 47. |
An example of non-perodic change isA. Change of fastB. chemical showC. Beating of heartD. Earthquakes |
| Answer» Correct Answer - D | |
| 48. |
The Latin name of potassium is `"_____"` |
| Answer» Correct Answer - Kalium | |
| 49. |
The number of atoms in one molecule of oxygen is `"_____"` |
| Answer» Correct Answer - two | |
| 50. |
Match the followign based on the number of atoms present in one molecule. |
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Answer» Correct Answer - `(A) to (b),(B) to (d), (C )to (f), (D) to (a) ,(E ) to (C ) , (F) to (e )` `CO_(2),Na_(2)OrArr 3 " atoms "` `AICI_(3) ,SO_(3) rArr 4 " atom "` `CaCO_(3) ,CH_(4) rArr 5 " atoms "` `HCI,FeS rArr 2 " atoms "` `Na_(2)CO_(3),CuSO_(4) rArr 7 " atoms "` `H_(2)SO_(4) H_(3)PO_(3) rArr 7 " atoms "` `(A) to (b) : (B) to (d),( C ) to (f)` `(D) to (a), (E) to (c) ,(F) to (e)` |
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