Question

9. Which of the following amines can be prepared by ring opening of an epoxide with sodium amide followed by reduction? CH OH Em Em a. only 1 b. only 1 and 2 c. only 1 and 4 d. 1, 2, 3 and 4 10. What is the IUPAC name of the following compound? OH HO. Y OH ÕH a. (2R 3R)-dihydroxybutanedioic acid b. (2S,3S)-dihydroxybutanedioic acid C. (2R,3S)-dihydroxybutanedioic acid d. (2S,3R)-dihydroxybutanedioic acid 11. Which of the following is the correct order of decreasing acid strength (more acidic > less acidic)? a. FCH2COOH > CH3COOH > F2CHCOOH b. FCH2COOH > CH3COOH > CH, OH c. CH,CH,OH > CICH,COOH > BrCH,COOH d. CH COOH > CICH,COOH > CH OH 12. Which of the following carboxylic acids undergoes the most rapid thermal decarboxylation reaction? ayla line mouc WN -

Answer 1

(20) 2,3-dihydroxybutanedioic acid is known as tartaxic acid. Its correct Rls Configuration comes out to be (s,s) and known as (5, 5)-(-)-tartanic acid. Therefore, the correct option is (b). (11). distance of . As the distance of withdrawing group increases worst the Carboxyl group (-Cooh), the acidity of the Carboxylic acid decreases. for example :-(h*(-c-OH > He-CH₂-C-on. Carboxylic acids are more acidic than alcohol due to the higher stability of Carboxylate anion (A coo) as compared to alkoxide lon (R-00). for example :- I Resonance co stablisation The anion is further stablired by the - I effect of fluorine atom.

H-00 = No resonance stablication. Therefore the correct decreasing order of the acidity is - fch, Cool > CHCOOH 7 CHON

(12) The general Mechanism for decarboxylation is - (2) Red Base - Rego + BH (where R= any group) (1) Rere - R og Higher the stability of Ro formed, more easily the decarboxy- lation will take place . . - OR when the acid attatched to the has a withdrawing x- carbon then a function such as (c=0) cyclic elemination process occur. satisfies the In the given examples only Condition . inhih (withdrawing group) Wat com therefore, the correct option && (C).