Class 11 Ch-12 Organic Chemistry-Some Basic Principles and Techniques (VSQ)

Q.1. What type of isomerism is shown by butane and isobutane?

Answer Answer: Chain or nuclear isomerism.

Q.2. Write the metamer of diethyl ether. What is its IUPAC name ?

Answer Answer: 1-Methoxypropane, CH3OCH2CH2CH3 or
2-methoxypropane, CH3-OCH(CH3)2.

Q.3. What is the functional group of (i) an aldehyde and (ii) a nitro compound?

Answer Answer: (i) –CHO (II) –NO2

Q.4. What primary and secondary suffixes are as applied to IUPAC nomenclature?

Answer Answer: The primary suffix indicates whether the carbon chain is saturated or unsaturated while the secondary suffix indicates the functional group present in the molecule.

Q.5. Give the IUPAC name of the compound: CH2 = CH – CH(CH3)2

Answer Answer: 3-Methylbut-l-ene.

Q.6. An organic liquid decomposes below its boiling point. How will you purify it ?

Answer Answer: Distillation under reduced pressure, i. e., vacuum distillation.

Q.7. Two volatile compounds A and B differ in their boiling points by 15 K. Suggest a suitable method for their separation.

Answer Answer: By fractional distillation.

Q.8. How will you separate a mixture of o– and p– nitro phenols?

Answer Answer: o–nitro phenol is steam volatile while p–nitro phenol is not and hence these can be separated by steam distillation.

Q.9. Name two methods which can be safely used to purify aniline.

Answer Answer: Vacuum distillation and steam distillation.

Q.10. What type of organic compounds cannot be Kjeldahlised?

Answer Answer: Compounds containing nitrogen atom in the ring and those compounds in which nitrogen is directly linked either to oxygen or to another nitrogen atom such as in nitro (–NO2) and azo (–N = N) compounds.

Q.11. Define the term ‘elution’ as applied to column chromatography.

Answer Answer: It is the process of extraction of different compounds adsorbed on the column by means of a suitable solvent called eluent.

Q.12. Define homologous series.

Answer Answer: Refer textbook.

Q.13. Give the IUPAC names of the following compound:

Answer Answer: 2-Bromo-4-methylpentan-3-one.

Q.14. Name the process of separating benzoic acid and naphthalene.

Answer Answer: Fractional crystallisation using benzene as a solvent.

Q.15. What is the suitable adsorbent in the process of column chromatography?

Answer Answer: Al2O3 (alumina).

Q.16. Which gas is liberated in Kjeldahl’s method?

Answer Answer: Ammonia gas (NH3).

Q.17. What is the value of ‘x’ in an organic compound with molecular formula CxH12 with vapour density 42?

Answer Answer: V.D. is 42, Mol. wt. = 2 × V.D. = 2 × 42 = 84 therefore, molecular formula is C6H12.

Q.18. Which gas is liberated in Duma’s method?

Answer Answer: N2.

Q.19. Why are melting point and refractive index used as the criteria of purity of organic compounds?

Answer Answer: Every pure substance has fixed melting point and refractive index. Impurities reduce the melting point and change refractive index.

Q.20. Name the gas displaced in Victor Meyer’s method.

Answer Answer: Air.

Q.21. In order to determine the molecular mass of benzene, which method would you use?

Answer Answer: Victor-Meyer’s method because it is volatile liquid.

Q.22. Why does hydrazine not give test for Lassaigne’s extract?

Answer Answer: It does not contain carbon, therefore, it is not an organic compound.

Q.23. Complete the following :
(CH3COO)2 Pb + Na2S ®

Q.24. Is neopentyl radical, 4°?

Answer Answer: No. It is 1°.

Q.25. It is advisable to prepare Lassaigne’s extract in distilled water. Why?

Answer Answer: Tap water usually contains dissolved chlorine which gives test for halogens.

Q.26. Write the IUPAC name of

Answer Answer: 2, 4-dimethyl-5-oxopentanoic acid.

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