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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.
| 451. |
Why are alkanes called paraffins? |
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Answer» Paraffins means little affinity; alkanes due to strong C-C and C-H bonds are relatively chemically inert. |
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| 452. |
What are alkanes? Why are they called paraffins? |
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Answer» Those hydrocarbons which contain single bond between carbon- carbon are called alkanes. They are called paraffins because they are very less reactive (Latin- Parum= little, affins = affinity) |
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| 453. |
Which of the following reaction does not involve a `C-C` bond formation?A. Hydrolysis of a Grignard reagentB. Combination of two alkyl free radicalsC. Corey-House synthesis of alkanesD. `RN a+R-BrtoR-R+NaBr` |
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Answer» Correct Answer - A In hydrolysis of GR.R-Mg or C-Mg bond breaks. |
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| 454. |
Acetic acid is the only product of ozonolysis ofA. `1-`ButyneB. Dimethyl acetyleneC. Ethyl acetyleneD. `2-` Butene |
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Answer» Correct Answer - b Acetic acid is the only product of ozonolysis of dimethyol acetylene. `CH_(3)-C-=C-CH_(3)+O_(3)overset(H_(2)O)rarrunderset("ethanoic acid")(2CH_(3)COOH)+H_(2)O_(2)` |
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| 455. |
Alkene can be formed from carbonium ion byA. Combination of protonB. Elimination of hydride ionC. Elimination of protonD. First combination of H then removal of H |
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Answer» Correct Answer - D `underset(("By base"))(underset(H)underset(|)(C)H_(2)-CH_(2)^(+)overset(-H^(+))toCH_(2)=CH_(2))` |
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| 456. |
Acetylene givesA. White ppt. with `AgNO_(3)` and re ppt. with `CuCl_(2)`B. White ppt. with `Cu_(2)Cl_(2)` and red ppt. with `AgNO_(3)`C. White ppt. with bothD. Red ppt. with both |
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Answer» Correct Answer - A `Cag-= Cag` is white and `CuC-= C Cu` is red. |
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| 457. |
Which product is obtained as a major product when one mol of HBr is added to one mol of 1,3-butadiene at 193K?A. `CH_(2)Br-CH_(2)-CH=CH_(2)`B. `CH_(3)-CHBrCH-CH_(2)`C. `CH_(3)CH-CHCH_(2)Br`D. `CH_(3)-CH=CBrCH_(3)` |
| Answer» Correct Answer - B | |
| 458. |
Reaction of one molecule of HBr wit one moleculae 1,3-butadiene at `40^(@)C` gives predominnantlyA. 3-bromobutene under kinetically controlled conditionsB. 1-bromo-2-butene under thermodynamically controlled conditionsC. 3-bromobutene under thermodynamically controlled conditionsD. 1-bromo-2-butene under kinetic controlled conditions |
| Answer» Correct Answer - B | |
| 459. |
Which one is the correct order of acidity ?A. `CH-=CH gt CH_3 -C -=CH gt CH_2 =CH_2 gt CH_3 -CH_3`B. `CH-=CH gt CH_2 =CH_2 gt CH_3 -C -=CH gt CH_2- CH_3`C. `CH_3-CH_3 gt CH_2 =CH_2 gt CH_3 -C -= CH gt CH-=CH`D. `CH_2=CH_2 gt CH_3 -CH=CH_2` |
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Answer» Correct Answer - A `+I`-Effect of `CH_3` group increases the electron-density in the C-H bond thereby decreasing its tendency to release a proton. Thus, propyne is less acidic than ethyne. Thus, the acidity of ethane, ethene , ethyne and propyne decreases in the order : option (a) is correct. |
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| 460. |
The correct order of rate of following reactions is `CH_(3)-C=C-CH_(3)overset(HBr(1 eq.))underset(eta)rarr(X) overset(HBr(1 eq.))underset(r_(2))rarr (Y)` `H-C -=C-H overset(HBr(1 eq.))underset(r_(3))rarr(Z)` `CH_(3)-CH=CH-CH_(3) overset(HBr(1 eq.))underset(r_(4))rarr(W)`A. `r_(4)gtr_(2)gtr_(1)r_(3)`B. `r_(1)gtr_(2)gtr_(3)gtr_(4)`C. `r_(4)gtr_(3)gtr_(2)gtr_(1)`D. `r_(3)gtr_(4)gtr_(2)gtr_(4)` |
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Answer» Correct Answer - a Alkenes are more reactive than alkynes. More branched alkynes are more reactive. |
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| 461. |
Identify ‘A’ in the following reaction :a. KMnO4/H+ b. alkaline KMnO4 c. dil.H2SO4/1% HgSO4d. NaOH/H2O2 |
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Answer» Option : a. KMnO4/H+ |
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| 462. |
(P), product (P) is:A. B. C. D. |
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Answer» Correct Answer - b Alkoxymercuration-De-mercuation reaction. |
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| 463. |
Product of the reaction is:A. B. C. D. |
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Answer» Correct Answer - b cis-diol will form |
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| 464. |
What is the major product expected from the following reaction? A. B. C. D. |
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Answer» Correct Answer - b cis-diol will form (syn addition takes place) |
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| 465. |
: Reagent (A) in the reaction is:A. `O_(3)//Zn(H_(2)O)`B. `HIO_(4)`C. `CrO_(3)`D. Cold dil. `KMnO_(4)` |
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Answer» Correct Answer - a Alkane will be cleaved by ozonolysis. |
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| 466. |
`CH_(3)-CH=CH_(2)overset(Br_(2)//hv)underset(("low conc."))(to)(A)`, Product (A) of the reaction is:A. `CH_(3)-underset(Br)underset(|)(C)H-CH_(2)-Br`B. `H_(2)C=CH-CH_(2)-Br`C. `CH_(3)-underset(Br)underset(|)(C)=CH_(2)`D. `Br-CH_(2)-CH_(2)-CH_(2)-Br` |
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Answer» Correct Answer - b `Br_(2)//hv`(low conc.) (or) N.B.S, Allylic free radical substituation reaction. |
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| 467. |
Arrange the following in the increasing order of C-C bond length- C2H6 C2H4C2H2 |
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Answer» C2H2<C2H4<C2H6 |
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| 468. |
Name two reagents which can be used to distinguish between ethene and ethyne. |
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Answer» Tollen's reagent and ammoniacal C. |
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| 469. |
Out of ethylene and acetylene which is more acidic andwhy? |
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Answer» Acetylene, due to greater electonegativity of the sp hybrid carbon. |
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| 470. |
Name two reagents which can be used to distinguish between ethene and ethyne. |
| Answer» Tollen‘s reagent... | |
| 471. |
Discuss the laboratory preparation of Acetylene? |
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Answer» Acetylene is prepared in the laboratory as well as in the industrial scale by the reaction of water on calcium carbide CaC2 + 2H2O--------> CH≡CH + Ca(OH)2 Calcium carbide is prepared by heating quick lime with coke. Quick lime can be obtained by heating limestone as shown in the following reactions: CaCO3 ⎯ Δ → CaO + CO2 CaO + 3C ⎯→ CaC2 + CO Calcium Carbide |
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| 472. |
Out of ethylene and acetylene which is more acidic and why? |
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Answer» Acetylene, due to greater electonegativity of the sp hybridised carbon. |
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| 473. |
Arrange the following in the increasing order of C-C bond length- C2H6 , C2H4, C2H2. |
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Answer» C2H2 < C2H4 < C2H6 |
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| 474. |
Which is incorrect statement about heats of combustion?A. B. C. Iso-butene gt trans-2-butene gt 1-buteneD. n-Hexane lt n-Heptane lt n-octane |
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Answer» Correct Answer - c Iso-butene is most stable isomer of butene. `therefore` It have least heat of combustion. |
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| 475. |
`C_6H_5MgBr` reacts with methanol to give _______ and _________ |
| Answer» Correct Answer - `C_6H_6, Mg(OCH_3)Br` | |
| 476. |
Which method is preferred for the preparation of `n-`propyl chloride from benzene ?A. B. C. Both are undesirableD. Both give similar result |
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Answer» Correct Answer - b Wurtz`-` Fitting method is preferred since in this case, no rearranged product is formed. As far as other products, viz. `n-`hexane and biphenyl is concerned, these can be easily removed from `n-`propyl benzene by distillation since their boiling points differ very much form each other. |
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| 477. |
Which among the following is not a mets directing group?A. `-NO_(2)`B. `-SO_(3)H`C. `-COOH`D. `-OH` |
| Answer» Correct Answer - D | |
| 478. |
Benzene on ozonolysis yieldsA. GlyoxalB. AcetoneC. PropanolD. Butanone |
| Answer» Correct Answer - A | |
| 479. |
Solid methane isA. A molecular solidB. An ionic acidC. A covalent solidD. Amorphous |
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Answer» Correct Answer - A There is van der Waal bonding among `CH_(4)` molecules in the solid state, hence it is a molecular solid. |
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| 480. |
The slowest of abstraction of hydrogen atoms by a chlorine atoms is shown byA. `(CH_(3))_(3)-C-CH_(3)`B. `(CH_(3))_(3)CH`C. `C_(6)H_(5)CH_(3)`D. `CH_(2)=CHCH_(3)` |
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Answer» Correct Answer - A `(CH_(3))_(3)C-CH_(3) overset(-H^(@))to underset("least stable")((CH_(3))3C-CH_(2))` |
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| 481. |
Abstraction of a sec H-atm propane gives……..radicalA. n-PropylB. IsopropylC. EthylD. none of these |
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Answer» Correct Answer - B `underset("Propane")(overset(1^(@))(C )H_(3)-overset(2^(@))(C )H_(2)-overset(1^(@))(C )H_(3))rarr underset("Isopropyl free radical")(CH_(3)-overset(•)(C )H-CH_(3)+H^(•))` |
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| 482. |
In which of the following hydrocarbons would give a red precipitate on treatment with ammoniacal cuprous chlorideA. 2-ButeneB. 2-ButyneC. 1,3-ButadieneD. 1-Butyne |
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Answer» Correct Answer - D 1-Butyne is a terminal alkyne. |
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| 483. |
Among the following, insecticide isA. `BHC`B. hospheneC. ChloralD. Aspirin |
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Answer» Correct Answer - a `BHC` is also known as benzene hexachloride `(C_(6)H_(6)Cl_(6))`. It is an insecticide and sold under the brand name gammexane. It is also known as `6,6,6.` |
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| 484. |
The distinguishing test for tiple bond containing acidic hydrogen isA. `AlCl_(3)`B. `Br_(20` in `C Cl_(4)`C. Alkaline `KMnO_(4)`D. `Ag(NH_(3))_(2)^(+)` |
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Answer» Correct Answer - d `Ag(HN_(3))_(2)^(+)` gives white ppt. with terminal alkynes. |
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| 485. |
Every carbon atom in alkanes is ………….. (A) sp hybridized (B) sp2 hybridized (C) sp3 hybridized (D) sp3 d hybridized |
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Answer» Correct option is: C) sp3 hybridized In Alkanes, every carbon atoms are \(sp^3\) Hybridized (C) sp3 hybridized |
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| 486. |
Isomerism is the phenomenon in which two or more organic compounds have …………. (A) same molecular formula but different structural formula (B) same structural formula but different molecular formula (C) same general formula, but different structural formula (D) same empirical formula, same structural formula |
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Answer» Correct option is: (A) same molecular formula but different structural formula Isomerism is the phenomenon in which two or more organic compounds have same molecular formula but different structural formula (A) same molecular formula but different structural formula |
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| 487. |
What do you mean by pyrolysis? |
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Answer» The decomposition of a compound by the heat is called pyrolysis. This process, when applied to alkanes, is known as cracking. |
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| 488. |
Arrange the three isomers of pentane in increasing order of their boiling points? |
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Answer» 2, 2-Dimethylpropane<2- methyl butane<n-pentane |
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| 489. |
Write physical properties of alkenes. |
Answer»
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| 490. |
Arrange the following alkenes in increasing order of their boiling points. But-1-ene, 2,3-dimethylbut-2-ene, 2- methylpropene, propene, 2-methylbut-2-ene. |
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Answer» Propene < 2-methylpropene < but-1-ene < 2- methylbut-2-ene < 2,3-dimethylbut-2-ene. Note: Melting points and boiling points of alkenes.
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| 491. |
The intermediate carbocation formed in the reactions of HI, HBr and HCl with propene is the same and the bond energy of HCl, HBr and HI is 430.5 kJ mol–1, 363.7 kJ mol–1 and 296.8 kJ mol–1 respectively. What will be the order of reactivity of these halogen acids? |
| Answer» Bond dissociation energy is least for HI and maximum for HCl therefore, order of reactivity will be HI > HBr > HCl. | |
| 492. |
which reaction will occur at the fastest rate?A. B. C. D. |
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Answer» Correct Answer - d More the stable carbocation more is rate. |
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| 493. |
Di-imid`(N_(2)H_(4))` is used to reduce double bond of:A. `-underset(|)(C)=O`B. `-C-=N`C. `-NO_(2)`D. `-CH=CH-` |
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Answer» Correct Answer - d Di-imide is used to reduce pi-bond formed between like atom. For example `to -CH=CH-,-N=N-` It can be reduced following gps. `to-overset(O)overset(||)C-,--overset(N)overset(||)C-,-N=O,-C-=N-NC`, |
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| 494. |
`H_(3)C-CH=CH_(2)+HCl` the intermediate of reaction is:A. `CH_(3)-CH-CH_(3)`B. `CH_(3)-CH_(2)CH_(2)`C. `CH_(3)-CH_(-CH_(3)`D. `CH_(3)-CH_(2)-CH_(2)` |
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Answer» Correct Answer - C No peroxide effect by HCI,so reaction take place by carbocation. |
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| 495. |
What is the use of BHC (benzene hexachloride)? |
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Answer» It is used as an insecticide under the name of Gammexane or lindane. |
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| 496. |
Choose the odd one out (a) Straws (b) Foam cups (c) Diapers (d) Toys |
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Answer» (b) Foam cups. It is made up of polystyrene whereas others are made up of polypropylene |
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| 497. |
Choose the correct pair (a) PET : shampoo bottles (b) PS : disposable utensils (c) PP : grocery bags (d) HDPE : plastic pipes |
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Answer» (b) PS : disposable utensils |
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| 498. |
The compounds which contain at least one benzene ring are …………. (A) aliphatic compounds (B) aromatic compounds (C) cycloalkanes (D) both (A) and (B) |
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Answer» Correct option is: (B) aromatic compounds The compound which contain at least one benzene ring are called aromatic compounds (B) aromatic compounds |
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| 499. |
γ-isomer of BHC is known as …………. (A) gammene (B) gammaxane (C) chlorobenzene (D) hexachlorobenzene |
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Answer» Correct option is: (B) gammaxane \(\gamma\)-isomer of BHC is known as (B) gammaxane |
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| 500. |
X-Ray diffraction reveals that benzene is a …………. structure. (A) triangular (B) planar (C) co-planar (D) 3D |
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Answer» Correct option is: (B) planar X- ray diffraction reveals that benzene is a planar structure Correct option is (B) planar |
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