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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. |
Which of the following pair are called functional isomers?(a) methyl propyl ether and diethyl ether(b) 2-pentanone & 3-pentanone(c) propanoic acid and methyl acetate(d) I -butanol and 2-butanol |
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Answer» (c) propanoic acid and methyl acetate |
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| 452. |
Which isomerism is not shown by alkene ?(A) chain(B) geometrical(C) position(D) metamerism |
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Answer» (D) metamerism |
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| 453. |
Functional isomers of propionic acids are ...... .(A) HCOOC2H5 and CH3 COOCH3(B) HCOOC2H5 and C3H7 COOH(C) C3H7OH and CH3COCH3(D) CH3CH2COOH and C3H7OH |
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Answer» (A) HCOOC2H5 and CH3 COOCH3 |
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| 454. |
Which isomerism is ehibited by C5H10O ?(A) Position(B) Functional group(C) Metamerism(D) All the given |
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Answer» (D) All the given |
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| 455. |
How many isomers of C6H14 are possible ?(A) 3 (B) 4 (C) 5 (D) 6 |
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Answer» 5 isomers of C6H14 are possible. |
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| 456. |
In Dumas’ method for estimation of nitrogen, 0.3 g of an organic compound gave 50 mL of nitrogen collected at 300K temperature and 715 mm pressure. Calculate the percentage composition of nitrogen in the compound. (Aqueous tension at 300K=15 mm). |
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Answer» Volume of nitrogen collected at 300K and 715mm pressure is 50 mL Actual pressure = 715-15 =700 mm Volume of Nitrogen at STP=273*700*50/300*760 =41.9 ml 22400 ml of Nitrogen at STP weighs = 28 g 41.9 ml of Nitrogen weighs = 28*41.9/22400 g % of Nitrogen = 28*41.9*100/22400*0.3 = 17.45 % |
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| 457. |
In Dumas’ method for estimation of nitrogen, 0.3g of an organic compound gave 50mL of nitrogen collected at 300K temperature and 715mm pressure. Calculate the percentage composition of nitrogen in the compound. (Aqueous tension at 300K=15 mm). |
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Answer» Volume of nitrogen collected at 300K and 715mm pressure is 50 mL Actual pressure = 715-15 =700 mm Volume of nitrogen at STP =273 *700 *50/300 *760 = 41.9 mL 22,400 mL of N2 at STP weighs = 28 g 41.9 mL of nitrogen weighs=28 *41.9 /22400g Percentage of nitrogen =28 *41.9* 100/22400* 0.3 =17.46% |
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| 458. |
Why is impure glycerol purified by distillation under reduced pressure? |
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Answer» At normal pressure, the boiling point of glycerol is 563 K but it decomposes on this temperature Therefore, simple distillation cannot be used. Under a reduced pressure of 12 mm Hg, the glycerol can be distilled at 453 K without decomposition. |
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| 459. |
Lassaigne's extract is prepared in distilled water and not in tap water. Explain. |
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Answer» The tap water generally contains chloride (CI−) ions. Therefore, it cannot be used to test the presence of chlorine in an organic compound. Therefore, the Lassaigne's extract is prepared in distilled water. |
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| 460. |
It is advisable to prepare Lassaignes extract in distilled water why? |
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Answer» Tap water usually contain dissolved chlorine which gives test for halogen. |
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| 461. |
A liquid with high boiling point decomposes on simple distillation but it can be steam distilled for its purification .Explain how is it possible? |
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Answer» In steam, distillation boiling occurs when the vapour pressure of organic compound & steam becomes equal to atmospheric pressure. As vapour pressure of water is higher than the organic liquid. Therefore, organic liquid vaporizes at a temperature below its boiling point in steam distillation without decomposing. |
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| 462. |
In the following questions, a statement of Assertion (A) is given followed by a corresponding statement of Reason (R) just below it. Of the statements, mark the correct answer as –(a) If both assertion and reason are true, and reason is the true explanation of the assertion.(b) If both assertion and reason are true, but reason is not the true explanation of the assertion.(c) If assertion is true, but reason is false.(d) If assertion is false ,but reason is true.Assertion (A). All compounds having C=C bond exhibit geometrical isomerism.Reason (R). Rotation about C=C bond is restricted. |
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Answer» (d) If assertion is false ,but reason is true. |
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| 463. |
Which metal is used to prepare Lassaigne’s extract?(a) Copper (b) Sodium (c) Aluminium(d) Iron |
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Answer» (b) Sodium Sodium is used to prepare Lassaigne’s extract. |
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| 464. |
Explain ,why an organic liquid vapourises at a temperature below its boiling point in steam distillation? |
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Answer» Because for boiling to occur vapour pressure of organic compound & steam should be equal to atmospheric pressure. As vapour pressure of water is higher than organic liquid. Therefore, organic liquid vaporizes at a temperature below its boiling point in steam distillation. |
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| 465. |
Explain, why an organic liquid vapourises at a temperature below its boiling point on steam distillation? |
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Answer» It is because in steam distillation the sum of vapour pressure of organic compound and steam should be equal to atmospheric pressure. |
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| 466. |
Steam distillation is used for the extraction of …….. |
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Answer» essential oils |
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| 467. |
Explain about azeotropic distillation. |
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Answer» The mixture of liquids that cannot be separated by fractional distillation can be purified by azeotropic distillation. The mixture are called azeotropes. These azeotropes are constant boiling mixture which distill as a single component at a fixed temperature for example ethanol and water in the ratio of 95.87: 4.13. In this method, the presence of a third component C6H6 , CCl4 , ether, glycol glycerol which act as dehydrating agent depress the partial pressure of one component of azeotropic mixture and raises the boiling point of that component and thus the other component will distil over. Substance like C6H6, CCl4 have low b.pt. and reduce the partial vapour pressure of alcohol more than that of water while substance like glycerol and glycol have high boiling point and reduce the partial vapour pressure of water more than that of alcohol. |
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| 468. |
(a) What is Lassaigne’s extract? Will NaCN give a positive Lassaigne’s test for nitrogen?(b) Which colour will appear in the Lassaigne’s test if the compound contains both nitrogen and sulphur.(c) Why is Lassaigne’s extract prepared in distilled water? Can we detect oxygen iii a compound by Lassaigne’s test? |
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Answer» (a) When organic compounds is fused with sodium metal and then extracted by water it is called Lassaigne’s extract. Yes. (b) Blood red colour. (c) Lassaigne’s extract is prepared in distilled water since ta water contains Cl’ ions. No, oxygen cannot be detected by Lassaigne’s test. |
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| 469. |
Under what conditions can the process of team distillation is used? |
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Answer» Steam distillation is used to purify the Liquids which are steam volatile and not miscible with water. |
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| 470. |
Write the functional group of – 1. thiocyanate 2. isothiocyanate 3. thiols 4. thioether |
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Answer» 1. Thio cyanale -SCN 2. Isothiocyanate -NCS 3. thiols -SH 4. thicethers -S |
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| 471. |
What is the difference between distillation, distillation under reduced pressure and steam distillation? |
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Answer» Distillation: it is used in case of volatile liquid mixed with a nonvolatile impurities. Distillation under reduced pressure: This method is used to purify such liquids which have very high boiling points and which decompose at or below their boiling points. Steam distillation: it is used to purify steam volatile liquids associated with water immiscible impurities. |
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| 472. |
Write the formulas for the first five members of each homologous series beginning with the following compound: H-CH=CH2 |
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Answer» H-CH=CH2 CH3CH=CH2 CH3CH2CH=CH2 CH3CH2CH2CH=CH2 CH3CH2CH2CH2CH=CH2 |
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| 473. |
What is the expected bond angle in the molecule in which the central atom is sp3 hybridized ?(A) 109° 28°(B) 120°(C) 90°(D) 180° |
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Answer» (A) 109° 28° |
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| 474. |
(a) What is homologous series?(b) What is the difference in the molecular formula of any two adjacent homologues:(i) in terms of molecular mass,(ii) in terms of number and kind of atoms per molecule? |
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Answer» (a) A homologous series is a group of organic compounds having a similar structure and similar chemical properties in which the successive compounds differ by a CH2 group. (b) The difference in molecular formula of any two adjacent homologues is (i) It differs by 14 a.m.u in terms of molecular mass. (ii) It differs by three atoms. The kind of atoms it differs is one carbon and two hydrogen. |
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| 475. |
The principle involved in paper chromatography is-a)adsorption b)partition c)solubility d)volatility |
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Answer» b) partition |
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| 476. |
Identify the substance underlined – An organic compound containing – COOH functional group. |
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Answer» Ethanoic acid [CH3—COOH] |
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| 477. |
Identify the term or substance based on the descriptions given below: 1. Ice like crystals formed on cooling an organic acid sufficiently. 2. Hydrocarbon containing a triple bond used for welding purpose. 3. The property by virtue of which the compound has the same molecular formula but different structural formulae. 4. The compound formed where two alkyl groups are linked by group. |
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Answer» 1. Glacial acetic acid 2. Ethyne or acetylene 3. Isomerism 4. Ketone or Alkanone |
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| 478. |
Which of the following carboxylate ions is the most stablea)CH3COO-b) ClCH2COO-c)FCH2COO-d)F2CHCOO- |
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Answer» (d) F2CHCOO- |
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