One Mark => CHAPTER 12 Organic chemistry - Some Basic Principles

One Mark Questions

Q.1. Suggest a method to purify a liquid which decomposes at its boiling point.
Ans.  The process Distillation Under reduced pressure is used to purify a liquid which decomposes at its boiling point.

Q.2. How will you separate a mixture of O-nitrophenol and p- nitrophenol ?
Ans o-nitrophenol is steam volatile therefore it can be separated by Steam distillation.

Q.3. Lassaigne‘s test is not shown by diazonium Salt. Why?
Ans. On heating diazonium Salts loses Nitrogen and could not fuse with the Sodium metal therefore diazonium Salt do not show Positive Lassaigne‘s test for nitrogen.

Q.4. Alcohols are weaker acids than Water, Why ?
Ans. The alkyl group in alcohols has + I effect due to which electron density is increased on Oxygen atom which makes the release of hydrogen ion more difficult from alcohol.R → O →H

Q.5. Why is nitric acid is added to Sodium extract before adding Silver nitrate for testing halogens ?
Ans.  Nitric acid is added to decompose NaCN and Na2S
NaCN + HNO₃ → NaNO₃ + HCN
Na₂S + 2HNO₃ → 2NaNO₃ + H₂S

Q.6. which of the two O₂NCH₂CH₂^-     or    CH₃CH₂O^– is expected to be more stable and why ?
Ans. NO₂ group has – I effect and disperse the negative charge on Oxygen atom
O₂N ←CH₂← CH₂O^-

Q.7. Arrange the following in increasing Order of Stability ;
(CH₃ )3C⁺ ,    CH₃CH₂CH₂C ⁺ H₂ ,      CH₃CH₂C⁺HCH₃ ,      CH₃C ⁺ H₂ ,       CH₃CH₂C ⁺  H₂
Ans.  CH₃C ⁺H₂ < CH₃CH₂C⁺ H2  < CH₃CH₂CH₂C ⁺H₂  <   CH₃CH₂2C ⁺ HCH₃  < (CH₃ )3C ⁺


Q.8. Write the IUPAC name of the following
CH₃  CH  CH      CH₂  CH₃
                 !          !
                 CH₃    CH₃

Ans. 2,3Dimethylpentane

Q.9. Write the hybridized state of C atoms in the following
CH2 = CH - C Ξ N
Ans. sp²sp²sp
        CH2 = CH - C Ξ N

Q.10. Give the IUPAC name of the following compound.

Ans.  2,5 Dimethylheptane.