PG TRB Online Test Chemistry

MARAN ACADEMY

PG TRB CHEMISTRY

  

ROTATE YOUR MOBILE SCREEN TO WRITE THE EXAM

 

1. .
   Allenes show optical activity because of the presence of
   
   1.   chiral carbon atom
   2.   conjugated double bond
   3.   isolated double bond
   4.   cumulated double bond
2. A molecule which is optically active
   1.   is asymmetric as a whole
   2.   contains at least three chiral centres
   3.   is super imposable on its mirror image
   4.   must be a meso compound
3. Enantiotropic groups react with chiral reagents
   1.   at different rate
   2.   at the same rate
   3.   same rate at the first and different rates later
   4.   do not react at all
4. .
   Which of the following definitions of an asymmetric reaction is the most accurate?
   
   1.   A reaction that creates a new chiral centre in the product
   2.   A reaction that involves a chiral reagent
   3.   A reaction that is carried out on an asymmetric starting material
   4.   A reaction that is carried out on an asymmetric starting material Enantiotropic
      groups react with chiral reagents
5. What is meant by a reaction going in 94% enantiomeric excess?
   1.   The product contains 94% of one enantiomer and 6% of the other enantiomer
   2.   The product contains 94% of one enantiomer and 6% of other products
   3.   The product contains an enantiomer which is 94% pure.
   4.   The product contains 97% of one enantiomer and 3% of the other enantiomer
6. .
   Two optical isomers are formed from carbon atoms to create bond
   
   1.   4 atoms
   2.   1 atoms
   3.   2 atoms
   4.   3 atoms
7. Stereoisomers that arise from restricted rotation about a single bond can be
   1.   Enantiomers
   2.   Diasteriosmers
   3.   Atropisomers
   4.   Epimers
8. Example of compound having axial chirality is
   1.   Allene
   2.   Compounds having asymmetric carbon
   3.   Meso Compounds
   4.   erytreo compounds
9. .
   Asymmetric synthesis can be done using
   1.   Anthraquinone
   2.   Quinoline
   3.   Benzaldehyde
   4.   Emulsin
10. Antifungal drug Mycomycin is a ------ derivative
    1.   Allene
    2.   Spirane
    3.   Biphenyl
    4.   Ansa
11. .
    The most stable conformation of Butane is
    
    1.   skew conformations
    2.   gauche conformations
    3.   eclipsed conformations
    4.   Anti conformations
12. A cisoid arrangement means to
    1.   eclipsed conformations
    2.   anti staggered conformations
    3.   skew conformations
    4.   gauche conformations
13. .
    The most unstable conformation of cyclohexane is
    
    1.   chair
    2.   half chair
    3.   wist-boat
    4.   boat
14. .
    In the complete rotation of butane from 0 degree to 360 degree the gauche-staggered conformation appears
    
    1.   once
    2.   twice
    3.   thrice
    4.   four times
15. .
    Trans bromine addition to cis-2-butene yields
    
    1.   D-2, 3-dibromobutane
    2.   l-2, 3-dibromobutane
    3.   racemic-2, 3-dibromobutane
    4.   meso-2, 3-dibromobutane
16. The conformation of cyclohexane which is free from all strain is
    1.   chair
    2.   half chair
    3.   twist
    4.   boat
17. . α- D (+) glucose and β- D (+)glucose are
    1.   Enantiomers
    2.   Diastereomers
    3.   Epimers
    4.   Anomers
18. .
    Which cycloalkane has the greatest ring strain?
    
    1.   Cyclopropane
    2.   Cyclobutane
    3.   Cyclopentane
    4.   Cyclohexane
19. In the most stable conformation of cis-1,4-dimethylcyclohexane, the methyl groups are:
    1.   both equatorial
    2.   both axial
    3.   one axial, one equatorial.
    4.   None of the above.
20. .
    The twist boat conformation is the preferred conformation for this compound.
    
    1.   trans-1,4-Di-tert-butylcyclohexane
    2.   cis-1,4-Di-tert-butylcyclohexane
    3.   trans-1,2-Di-tert-butylcyclohexane
    4.   cis-1,3-Di-tert-butylcyclohexane
21. .
    The Reformalsky reaction is often used for the preparing of
    
    1.   α-hydroxy ester
    2.   β-hydroxy ester
    3.   α-halo ester
    4.   β-halo ester
22. Ethyl acetoacetate is prepared from ethyl acetate by
    1.   Claisen condensation
    2.   Reformalsky reaction
    3.   Aldol condensation
    4.   Perkin reaction
23. Which of the following reaction undergoes the Grignard like reaction?
    1.   Aldol condensation
    2.   Reformalsky reaction
    3.   Wittig reaction
    4.   Perkin reaction
24. .
    Coumafin is prepared industrially from salicylaldehyde by
    
    1.   Stobbe reaction
    2.   Reformatsky reaction
    3.   Wittig reaction
    4.   Perkin reaction
25. In case of cyclic dienes the Diels-Alder reaction gives the end product exclusively at
    1.   low temperature
    2.   high temperature
    3.   all temperatures
    4.   at 0 degree celcius
26. Usually Diels-Alder reaction is
    1.   4 + 2 cyclo addition
    2.   2 + 2 cyclo addition
    3.   2 + 4 cyclo addition
    4.   none of the above
27. Esterification is quick in ------medium
    1.   Basic
    2.   Acidic
    3.   Neutral
    4.   Non polar
28. Aldehydes with lack of α-hydrogen undergoes disproportion reaction is
    1.   Wittig reaction
    2.   Reformatsky reaction
    3.   Cannizaro reaction
    4.   Perkin reaction
29. .
    The Claisen condensation is often used in preparing
    
    1.   β-hydroxy ester
    2.   β- keto ester
    3.   γ-keto ester
    4.   α-hydroxy ester
30. The intermediate formed in E1CB mechanism is
    
    1.   Carbonium ion
    2.   Depends on substrate
    3.   Carbanium
    4.   Free radical