InterviewSolution
Saved Bookmarks
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. |
Give the general formula of 'alkynes'. Identify the alkynes from the following: `CH_(4),C_(2)H_(6),C_(2)H_(2),C_(3)H_(4),C_(2)H_(4)` |
| Answer» The general formula of alkynes is `CnH_(2n-2)` whsere n is the number of carbon atoms in one molecule of the alkyne . Out of the above given hydrocarbons `C_(2)H_(2) and C_(3)H_(4)` are alkynes (because they correspond to the general formula `C_(n)H_(2n-2)` with n=2 and n=3, respectively) (please note that in an alkyne molecule, ' the number of hydrogen atoms' is ' 2 less than double the number of carbon atoms') | |
| 2. |
Write the structure of ethyl alcohol `(C_(2)H_(5)OH)`. |
| Answer» `H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-OH` | |
| 3. |
Vinegar is a solution ofA. 30%-40% acetic acid in alcoholB. 5%-8% acetic acid in alcoholC. 5%-8% acetic acid in waterD. 15%-20% acetic acid in water |
|
Answer» Correct Answer - C It is the correct answer. |
|
| 4. |
Which of the following molecular formula corresponds to ethyl butanoate ester?A. `C_(5)H_(10)O_(2)`B. `C_(6)H_(12)O_(2)`C. `C_(7)H_(14)O_(2)`D. `C_(8)H_(16)O_(2)` |
| Answer» Correct Answer - (b) | |
| 5. |
The usual disease caused by the excessiv edrinking of alcohol over a long period of time is :A. diabetesB. cataractC. cirrhosisD. arthritis |
| Answer» Correct Answer - (c ) | |
| 6. |
Ethanol reacts with sodium and forms two products. These areA. sodium ehanaoate and oxygenB. sodium ethanaoate and hydrogenC. sodium ethoxide and oxygenqD. sodium ethoxide and hydrogen |
| Answer» Correct Answer - (d) | |
| 7. |
Ethanol reacts with sodium and forms two products. These areA. sodium ethanoate and hydrogenB. sdium ethanoate and oxygenC. sodium ethaoxide and hydrogenD. sodium ethoxide and oxygen |
|
Answer» Correct Answer - C `2C_(2)H_(5)OH+2Natounderset("Sod. Ethoxide")(2C_(2)H_(5)ON a)+H_(2)` |
|
| 8. |
(a) Write chemcial name and formula of vinegar? (b) Desbribe with a chemical equation what happens when sodium reacts with ethanol. |
|
Answer» (a) The chemical name of vinegar is ethanoic acid. In fact, it is a dilute solution of ethanoic acid. Its chemical formula is `CH_(3)COOH`. (b) Hydrogen gas is evolved in the reaction and is accompanied by brisk effervescence. `underset("Ethanol")(2C_(2)H_(5)OH)+2Natounderset("Sod. ethaxide")(2C_(2)H_(5)ON a)+H_(2)`. |
|
| 9. |
Ethane with the molecular formula `C_(2)H_(6)` has: (a) 6 covalent bonds (b) 7 convalent bonds (c ) 8 covalent bonds (d) 9 convalent bonds |
|
Answer» `H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-H` (b) The molecular has seven covalent bonds |
|
| 10. |
Graphite is greasy, soft lubricant because itA. has low densityB. has weak forces of attraction between layersC. is greyish-black in colourD. has three dimensional structure. |
|
Answer» Correct Answer - B Graphite is greasy, soft lubricant becaue it has weak forces of attraction between layers. |
|
| 11. |
Why do black shoe polishes have an oily feel ?A. Shoe polish is a mixture of oil and powdere graphiteB. On exposure to air, thes undergo chemical changes and produces oily substances.C. Vapour of some amount of oil is left over after its preparation.D. These are formd by dissolving charcoal in oil. |
| Answer» Correct Answer - C | |
| 12. |
Vinegar is a solution ofA. `50%-60%` acetic acid in alcoholB. `5%-8%` acetic acid in alcoholC. `5%-8%` acetic acid in waterD. `50%-60%` acetic acid in water |
|
Answer» Correct Answer - C A `5%-8%` solution of acetic acid in water called vinegar. |
|
| 13. |
A buliding constructed from mortar becomes stronger on long standing. Give reason. |
|
Answer» (i) Constituents of mortar. (ii) Purpose of mortar in construction. (iii) Reaction between one of the components present in mortar with the component present in air. (iv) The percentage abundance of the above component present in air. (v) Relation between the availability of the reactant and the time taken for the reaction. |
|
| 14. |
Ethanol reacts with sodium and forms two products. These areA. sodium ethanoate and hydrogenB. sodium ethanoate and oxygenC. sodium ethoxide and hydrogenD. sodium ethoxide and oxygen |
|
Answer» Correct Answer - C Ethanol reacts with sodium to form sodium ethoxide and hydrogen gas. `underset("Ethanol")(C_(2)H_(2)OH)+underset("Sodium")(2Na)tounderset("Sodium ethoxide")(2C_(2)H_(5)O^(-)Na^(+))+underset("Hydrogen")(H_(2))uarr` |
|
| 15. |
Arrange the given combustible substance in decreasing order of calorific value. (a) Hydrogen (b) Charcoal (c ) Petrol (d) L.P.G ( e) WoodA. bcadeB. adcbeC. badecD. baced |
|
Answer» Correct Answer - B (i) Hydrogen (ii) L.P.G (iii) Petrol (iv) Charcoal (v) Wood |
|
| 16. |
________ acid on reaction with `H_(2)SO_(4)` gives only carbon monoxide gas. |
| Answer» Correct Answer - Formic | |
| 17. |
Discuss three importance uses of (i) Graphite (ii) Wood Charcoal (iii) Carbon monoxide (iv) Sugar charcoal (v) Bone charcoal (vi) Carbon dioxide (vii) Methane. |
|
Answer» (i) Lead of pencils, moderator in nuclear reactors, marking refractory crucibles. (ii) Deodrant and disinfectant , gas masks, fuel for keeping rooms warm in winter . (iii) Reducing agent in the extraction of metals, manufacture of chemicals , fuel. (iv) Extracting metals from their oxides, adsorbent material, making artificial diamonds. (v) Removes colour from sugarcane juice, extraction , of yellow phosphorous, fertilizer industries. (vi) Soft drinks or aerated drinks, fire extiguishers, production of industrial compounds. (vii) Fuel, parent hydrocarbon for halogenations reactions, water gas preparation. |
|
| 18. |
Draw the structures for the following compounds. (i) Ethanoic acid , (ii) Bromopentane (iii) Butanone , (iv) Hexanal |
|
Answer» The structures for ethanoic acid, bromopentane, butane and hexanal are given below: (i) `H-underset("Ethanoic acid")underset(H)underset(|)overset(H) overset(|)(C)-overset(O)overset(||)C-OH` (ii) `H-underset(H)underset(|)overset(H)overset(|)(C)-underset("Bromopentane") underset(H)underset(|)overset(H)overset(|)(C)-underset (H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-Br` (iii) `underset("Butanone")(H-underset(H)underset(|)overset(H)overset()(C)-underset(H)underset(|)overset(H)overset(|)(C)-overset(O)overset(||)(C)-underset(H)underset(|)overset(H)overset(|)(C)-H)` (iv) `underset("Hexanal")(H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-overset(O)overset(||)C-H)` Yes structural isomers are possible for bromopentane. Depending upon whether bromine atom is attached to carbon atom number 1,2 or 3 bromopentane can have three structural isomers : 1-bromopentane, 2-bromopentane and 3-brompoentane. These isomers are shown below: `underset(1-"bromopentane")(H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-Br)` `underset(2-"bromopentane")(H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(Br)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-H)` `underset(3-"bromopentane")(H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(Br)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-H)` |
|
| 19. |
Butanone is a four-carbon compound with the functional groupA. carboxylic acid.B. aldehyde.C. ketone.D. alcohol. |
| Answer» Correct Answer - (c) ketone. | |
| 20. |
Why is soda acid fire extinguisher used to extinguish fire caused by solid inflammable materials ? |
| Answer» Reaction between sodium bicarbonate and sulphuric acid gives carbon dioxide which is heavier than air and non-supporter of combustion. | |
| 21. |
Why is acitivated charcoal widely used in water purifiers ? |
|
Answer» (i) Properties of acticated charcoal. (ii) Surface area of activated charcoal. (iii) Effect of surface area on process of removal impurities. |
|
| 22. |
Out of HCl and `CH_(3)COOH`, which one is a weaker acid and why? Describe an activity to support your answer. |
|
Answer» `CH_(3)COOH` is a weaker acid than HCl. This is because of the reason that `CH_(3)COOH` is an organic acid whereas HCl is of inorganic nature. The degree of ionisation of HCl is more than that of `CH_(3)COOH`. Therefore, HCl gives more `H^(+)` ions in water as compared to `CH_(3)COOH` and it is a stronger acid. Activity: Dip strips of universal pH pape in given acids taken in two test tubes. It will acquire red colour in HCl ad orange colour in `CH_(3)COOH`. this clearly shows that HCl is a stronger acid. |
|
| 23. |
Butanone is a four-carbon compound with the functional groupA. `-COOH`B. `-CHO`C. `-CO-`D. `-OH` |
| Answer» Correct Answer - (c ) | |
| 24. |
Which of the following allotropes of carbon is used for the manufacture of fullerenes ?A. GraphiteB. DiamondC. CokeD. Charcoal. |
| Answer» Correct Answer - A | |
| 25. |
Why is graphite used as pencil lead ? |
|
Answer» (i) Structure of graphite. (ii) Type of bonding in graphite (iii) Colour of graphite |
|
| 26. |
Why does fogging occur while using a soda fire extinguisher ? |
| Answer» Carbon dioxide comes out with great force through a small nozzle from soda acid fire extinguisher. This reduces the temperature of the carbon dioxide to a great extent and moisture present in air condenses on the carbon dioxide molecules and appears like fog. | |
| 27. |
______ is used extensively in the manufacture of washing sodaA. Carbon dioxideB. Carbon monoxideC. MethaneD. Lamp black |
|
Answer» Correct Answer - A Carbon dioxide is used extensivly in the manufacture of washing soda. `CO_(2)+2NaOH to Na_(2)CO_(3)+H_(2)O` |
|
| 28. |
Compare and contrast the principle involved in the usage of of `NaHCO_(3)` and dry ice for cleaning industrial equipments by blasting the given substances with compressed air. |
| Answer» Soda blasting is a technique employed to strip off the paints and unwanted materials from all surfaces. This technique involved blasting of `NaHCO_(3)` on the required surface with the help of compressed air. Dry ice blasting is also used for the same purpose. But it is more advantageous than soda blasting because dry ice pellets sublime as soon as they are blasted on any surface leaving no residual matter on the surface. Since huge amount of heat is absorbed for sublimation process, thermal shock ( due to sudden contraction ) in generated in the coating which is an added advantages for the removal of unwanted coating. | |
| 29. |
Compare and constrat the principle involved in the usage of `NaHCO_(3)` and dry ice for cleaning industrial equipments by blasting the given substances with compressed air. |
|
Answer» (i) Effect on the unwanted coating due to the blasting of soda or dry ice. (ii) Nature of sodium bicarbonate. (iii) Mechanical impact on the industrial equipment due to blasting of `NaHCO_(3)` and dry ice. (iv)} Changes that takes place in dry ice after blasting. (v) Change in temperature due to the above phenomenon. (vi) Effect of change in temperature on the coating of impurities on the surface of industrial equipments. |
|
| 30. |
What do we get when ethanoic aid reacts with ethanol in the presence of concentrated sulphuric acid? |
| Answer» Ethyl ethanoate `(CH_(3)COOC_(2)H_(5))` is formed by esterification reaction. It has fuity smell. | |
| 31. |
An organic sompound A hs the molecular formula `C_(2)H_(4)O_(2)` and is aid in nature. On heating with ethanol and conc. `H_(2)SO_(4)` vapours with plaesant and fruity smell are given out. What is the compound A and what is the chemical equation involved in this reaction? |
| Answer» "The molecular formula of A is" `C_(2)H_(4)O_(2)` ."Sicne this compound is acidic in nature it should contain carboxylic acid group",-COOH. "If we subtract COOH group (1 carbon , 2 oxygen and 1 hydrogen atom) from" `C_(23)H_(4)O_(2)`, "we are left with 1 carbon atom and 3 hydrogen atoms which is a methyl group" , `CH_(3)` "combining" `CH_(3)` "and" COOH "we get" `CH_(3)COOH`. "Thus, compound A is ethanoic acid" `CH_(3)COOH` . "When ethanoic acid is warmed with ethanol in the presencve of conc". `H_(2)SO_(4)` a pleasant and fruity smelling ester, ethyl ethanoate is formed .(write the equation yourself). | |
| 32. |
Vapours of a hydrocarbon were passed through bromine dissolved in carbon tetrachloride. The yelow colour of bromine got discharged? Predict the nature of the hydrocarbon. |
| Answer» The hydrocarbon is unsaturated. It is either an alkene or alkyne. | |
| 33. |
Write chemical equation to represent each of the following types of reactions of organic substances. (i) Esterification, (ii) Saponification (iii) Substitution. |
|
Answer» (i) `underset("Ethanoic acid")(CH_(3)COOH)+underset("Ethanol")(C_(2)H_(5)OH)tounderset("Ethyl ethanoate")(CH_(3)COOC_(2)H_(5))+H_(2)O` (ii) `underset("Ethyl ethanoate")(CH_(3)COOC_(2)H_(5))+NaOHtounderset("Sod. Ethanoate")(CH_(3)COONa)+underset("Ethanol")(C_(2)H_(5)OH)` (iii) `underset("Methane")(CH_(4)+Cl_(2))tounderset("Chloromethane")(CH_(3)Cl)+HCl` |
|
| 34. |
An unknown compound has the smell of vineger. Identiy |
| Answer» The compound is ethanoic acid also called acetic acid. | |
| 35. |
An organic compound A on heating with concentrated `H_(2)SO_(4)` forms a compound B which on addition of one mole of hydrogen in presence of Ni forms a compounds C. One mole od compound C on combustion form two moles of `CO_(2)` and three moles of `H_(2)O`. Identify the compounds A,B and C write the chemical equation of the reactions involved. |
|
Answer» (i) Since, compounds C on combustion froms two moles of `CO_(2)` and 3 moles of `H_(2)O`, therefore compound C must contain two carbon atoms and six hydrogen atoms. Thus, compounds C must be ethane `(C_(2)H_(6))`. `underset("Ethane"(C))(C_(2)H_(6))+underset("Oxygen")(7//2O_(2))overset("Heat")tounderset("Carbon dioxide")(2CO_(2))+underset("Water")(3H_(2)O)` Hence, A is ethanol `(CH_(3)CH_(2)OH)`. B is ethene `(CH_(2)=CH_(2))`. , C is ethane `(CH_(3)-CH_(3))`. (ii) Since, compound C is obtained by addition of 1 mole of `H_(2)` in presence of Ni to compound B, therefore, B must be ethene `(C_(2)H_(4))`. `underset("Ethene"(B))(CH_(2)=CH_(2))+H_(2)overset("Ni,heat")tounderset((C))underset("Ethane")(CH_(3))-CH_(3)` (iii) Since, compounds B is formed by heating compound A with conc. `H_(2)SO_(4)`, therefore, compound A must be ethanol `(C_(2)H_(5)OH)`. `underset("Ethanol")(CH_(3)CH_(2)OH)underset(("dehydration"))overset("Conc."H_(2)SO_(4),443)tounderset((B))underset("Ethene")(CH_(2))=CH_(2)+H_(2)O` |
|
| 36. |
Write the molecular formula of the first two members of the homologous series having functional group `gtC=O`. |
| Answer» There are `CH_(3)-overset(O)overset(||)(C)-OH_(3) and CH_(3)-overset(O)overset(||)(C)-CH_(2)CH_(3)`. | |
| 37. |
Give the formulae and IUPAC names of next two members of homologous series given below: (i) `C_(2)H_(6),(b)C_(2)H_(4),(c)CH_(3)OH,(d)HCOOH,(e)CH_(3)COCH_(3)` |
|
Answer» (a) `C_(2)H_(6),C_(3)H_(8)("Propane"),C_(4)H_(10)("Butene")` (b) `C_(2)H_(4),C_(3)H_(6)("Propane"),C_(4)H_(8)("Butene")` (c) `CH_(3)OH,C_(2)H_(5)OH("Ethanol"),C_(3)H_(7)("Propanol")` (d) `HCOOH,CH_(3)COOH("Ethanoic acid"),C_(2)H_(5)COOH("Propanoic acid")` (e) `CH_(3)COCH_(3),CH_(3)COC_(2)H_(5)("Butanone"),C_(2)H_(5)COC_(2)H_(5)("Pentanone")` |
|
| 38. |
Which of the following is the correct representation of electon dot structure of nitrogen ?A. `:overset(..)(N):overset(..)(N):`B. `:overset(.)(N)::overset(.)(N):`C. D. |
|
Answer» Correct Answer - D Both the N atoms have a complete octet after electron sharing. |
|
| 39. |
(a) What are esters? How are they formed? (b) Write two uses of esters? |
|
Answer» (a) Esters are the group of organic compounds which contain the function group `(-COOR)` called ester group. The value of R may change as `-CH_(3),-C_(2)H_(5),-C_(3)H_(7)` etc. A few example of esters are: `underset("Methylmethaoate")(H-overset(O)overset(||)(C)-OCH_(3))" "underset("Methylethanoate")(CH_(3)-overset(O)overset(||)(C)-OCH_(3))` Esters are formed as a result of chemical reaction called esterification. (b) Uses of esters (i) Esters have pleasent smell. These are used as flavouring agents and also in perfumes. (ii) Esters of glycerol known as triglycerides, are used in the manufacture of soaps. this reaction is called saponification reaction. |
|
| 40. |
The functional group present in propanal is :A. `-OH`B. `-COOH`C. `-CO-`D. `-CHO` |
| Answer» Correct Answer - (d) Ketone group, -CO- | |
| 41. |
Draw electron dot structures of (i) `C_(2)H_(4)` (ii) `C_(2)H_(5)OH`. |
|
Answer» (i) `H:overset(H)overset(..)(C): :overset(H)overset(..)(C):H` (ii) `H:underset(H)underset(..)overset(H)overset(..)(C):underset(H)underset(..)overset(H)overset(..)(C):underset(..)overset(..)(C):H` |
|
| 42. |
(a) Define the term functional group. Identify the functional group present in (i) `H-overset(O)overset(||)(C)-H` (ii) `H-underset(H)underset(|)overset(H)overset(|)(C)-overset(OH)overset(|)(C)=O` (b) What happens when 5% alkaline `KMnO_(4)` solution is added drop by drop to warm ethanol taken in a test tube? State the role of alkaline `KMnO_(4)` solution in this reaction. |
|
Answer» (a) For the definition o functional group, The functional groups present in the compound are: Aldehydic (al) and carboxyl group (oic acid): (b) Ethanol is oxidised to ethanoic acid. In tthis, dilute alkaline `KMnO_(4)` acts as an oxidising agent. `underset("Ethanol")(CH_(3)CH_(2)OH)+underset("(released from oxidising agent)")(2(O))tounderset("Ethanoic acid")(CH_(3)COOH)+H_(2)O` |
|
| 43. |
Draw the structure of a molecule of butanone. |
| Answer» `H-underset(H)underset(|)overset(H)overset(|)(C)-underset(H)underset(|)overset(H)overset(|)(C)-overset(O)overset(||)(C)-underset(H)underset(|)overset(H)overset(|)(C)-H" or "CH_(3)-CH_(2)-overset(O)overset(||)(C)-CH_(3)`. | |
| 44. |
One of the following molecular formula can represent two organic cpompounds having different functional groups .This molecular formula is :A. `C_(5)H_(12)O`B. `C_(5)H_(10)O`C. `C_(5)H_(10)O_(2)`D. `C_(5)H_(12)` |
| Answer» Correct Answer - (b) | |
| 45. |
Write the next higher homologue of the following: (i) `C_(3)H_(6)` (ii) `C_(5)H_(8)` |
|
Answer» (i) `C_(4)H_(8)` (ii) `C_(6)H_(10)`. |
|
| 46. |
Write the next homologue of propanol `(CH_(3)CH_(2)CH_(2)OH) and ` Butanal `(CH_(3)CH_(2)CH_(2)CHO)` |
| Answer» Butanol or butan-1-ol `(CH_(3)CH_(2)CH_(2)CH_(2)OH)` and Pentanal `(CH_(3)CH_(2)CH_(2)CH_(2)CHO)` | |
| 47. |
name two other elements apart from carbon ad hydrogen which are present in coal and petroleum. Write the chemical reaction when the combustion of these elements takes place on burning coal. |
|
Answer» The elements nitrogen and sulphur are also present in coal and petroleum. The products of combustion are listed. `N_(2)(g)+O_(2)(g)to2NO(g),2NO(g)+O_(2)(g)to2NO_(2)(g)` `S(g)+O_(2)(g)toSO_(2)(g),2SO_(2)(g)+O_(2)(g)to2SO_(3)(g)` |
|
| 48. |
A hydorcarbon molecule contins 4 hydrogen atoms. Give its olecular formula , if it is an : (i) alkane, (ii) alkne ,(iii) alkyne. |
|
Answer» (i) an alkane containing 4 hydrogen atoms in its molecule is methane , `CH_(4)` (ii) An alkne containing 4 hydrogen atoms in its molecule is ethene , ` C_(2)H_(4)` (iii) An alyne containing 4 hydrogen atoms in its molecule is propyne, `C_(3)H_(4)` |
|
| 49. |
The molecular formula of a homologue of butane is :A. `C_(4)H_(8)`B. `C_(3)H_(6)`C. `C_(4)H_(6)`D. `C_(3)H_(8)` |
| Answer» Correct Answer - (d) Ketone group, -CO- | |
| 50. |
Explain why cannot we have isomers of first three members of alkane family. |
| Answer» First three members of alkane family are methane `(CH_(4))`, ethene `(CH_(3)-CH_(3))` and propane `(CH_(3)-CH_(2)-CH_(3))`. Since there is no scope for branching in alkanes having upto three carbon atoms, therefore no isomerism is possible. | |