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Biomolecules

1. Imino acid among the following compounds is

Ans: Proline    
 

2. Vitamin(s) belong to terpene group is/ are 

Ans: A , E , K 4
 

3. Progesterone is useful-

Ans: as birth control agent And  for preparing the uterus for the implantation of the fertilized egg
 

4. At pH = 5, glycine exists as 

Ans: H3N+ - CH2COOH
 

5. If one strand of DNA has the sequence of bases A T G C T T G A, the sequence of bases in the complementary strand would be

Ans: T A C G A A C T
 

6. (i) Cellulose  n moles of D glucose 

    (ii) Starch   n moles of D Glucose 

 Enzymes A, B in the above reactions are respectively

Ans: Cellulase, Amylase 
 

7. α - D(+) glucose &  β - D(+) glucose are

Ans: Anomers

 

8. RNA & DNA are chiral molecules, this is mainly due to presence 0f         

Ans: D-sugars 

 

 

Organic Chemistry - Some Basic Principles and Techniques

 

1. The correct order of number of acidic hydrogens is
1) H3C - C ≡ C - CH3 > H3C - C ≡ C - H > H - C ≡ C - H
2) H - C ≡ C - H > H3C - C ≡ C - H > > H3C ≡ C - CH3
3) H - C ≡ C - H > H3C - C ≡ C - CH3 > > H3C - C ≡ C - H
4) H3C - C ≡ C - H > > H - C ≡ C - H > H3C - C ≡ C - CH3
Ans: (2)
Explanation: No. of acidic hydrogens present in H - C ≡ C - H is 2.
                       H3C - C ≡ C - H is 1, H3C - C ≡ C - CH3 is zero.

 

2. Tropolone is
1) aromatic compound                2) carbocyclic compound
3) non-benzenoid compound      4) all the above
Ans: (4)
Explanation:
    Aromatic, as it follows Huckel rule (4n + 2)Π = 6 e-, ring contains only carbons so carbocyclic, ring has 7 carbons so non - benzenoid.

 

3. Heterocyclic aromatic compound among the following is/ are
1) Furan             2) Thiophene            3) Pyridine          4) all the above
Ans: (4)
Explanation: Furan has ‘O’, Thiophene has ‘S’, Pyridine has ‘N’ in their rings. So all are heterocyclic.

 

1) 1 - chloro - 3 - methyl 6 - methoxy benzene        2) 4 - methoxy - 3 - chloro Toluene
3) 2 - chloro - 4 - methylanisole                                  4) all the above
Ans: (3)
Explanation: Follow lowest numbering from substituent of the base compound.

 

5. The colour of the precipitate given by organic compound containing phosphorus in Lassaigne’s test is
1) Yellow            2) Brown          3) Prussian blue          4) Black
Ans: (1)
Explanation: Phosphomolybdate ppt - Yellow colour.
Na3PO4 + 3 HNO H3PO4 + 3 NaNO3
H3PO4 + 12 (NH4)2MoO4 + 21 HNO (NH4)3PO4 . 12 MoO3 + 21 NH4NO3 + 12 H2O

 

6. The type(s) of isomerism exhibited by 5th member of alkyne series
1) chain          2) position          3) both 1 & 2           4) metamerism
Ans: (3)
Explanation: Hex - 3 - yne & 3 - methyl pent - 1 - yne = chain isomers.
                        Hex - 1 - yne & Hex - 2 - yne = position isomers.

 

7. Mobile phase in column chromatography, paper chromatography and thin layer chromatography are
1) liquid, liquid, liquid       2) solid, liquid, gas      3) liquid, gas, liquid     4) gas, liquid, liquid
Ans: (1)
Explanation: Liquid is mobile phase in all 3 types.

 

8. A solution of (-) - 1 - chloro - 1 - phenyl ethane in toluene racemises slowly in the presence of a small amount of SbCl5, due to the formation of
1) free radical          2) Carbocation          3) Carbanion         4) Carbene
Ans: (2)
Explanation:

 

9. Arrange the following compounds in the order of decreasing acidity.

1) II > IV > I > III       2) I > II > III >  IV        3) III > I > II > IV       4) IV > III > I > II
Ans: (3)
Explanation: in III (-M & -I), in I(-I), in II (+I, hyper conjugation), in IV (+M) effect are observed. Electron withdrawing group increases acidic strength.

 

10. The correct order of inductive effect occurs in vinylic or arylic system is
1) (CH3)3C - > (CH3)2CH - > CH3CH2 -     2) CH3CH2 - > (CH3)2CH - > (CH3)3C -
3) (CH3)2CH - > CH3CH2- > (CH3)3C -      4) (CH3)3C - > CH3CH2 - > (CH3)2CH -
Ans: (1)
Explanation: (CH3)3C - > (CH3)2CH - > CH3CH2 -

 

11. The increasing order of stability of free radicals is

Ans: (4)
Explanation: Stability is due to more number of C6H5 groups (delocalisation) and more number of hyper conjugative H atoms & +I effect in.

 

12. 0.5 g of an organic compound gave 124.4 ml of N2 by Duma’s method. The % of N in this compound is
1) 15.5              2) 31.1           3) 46.6            4) 7.8
Ans: (2)
Explanation:

 

13. 0.46 g of organic compound having sulphur on treatment with conc. HNO3 in a Carius tube and then with excess of BaCl2 produced 1.165 g of BaSO4. The % of S in this compound is approximately
1) 10           2) 25         3) 35          4) 40
Ans: (4)
Explanation:

 

14. In Carius method of estimation of halogen, 0.17 g of an organic compound gave 0.12 g of AgBr. The % of Br in the compound is
1) 40           2) 30           3) 20           4) 10
Ans: (2)
Explanation:

 

15. The type(s) of effect is observed in H3C - CH = CH -  - CH3
1) Mesomeric effect                     2) Inductive effect        
3) Hyper conjugation effect        4) all the above
Ans: (4)
Explanation:
             
   Inductive effect           Mesomeric
             and                            effect
  hyper conjugation effect

Hydrocarbons

16. Chlorobenzene directs the incoming electrophile to the position(s)
1) ortho & para        2) meta          3) ortho & meta         4) meta & para
Ans: (1)
Explanation: due to +R effect of Cl atom.

 

17. Reaction of HBr with propene in the presence of peroxide gives
1) allyl bromide     2) n - propyl bromide      3) isopropyl bromide       4) 3 - bromo propane
Ans: (2)
Explanation:

 

18. Of the 5 isomeric hexanes, the isomer which can give two mono chlorinated compounds is
1) 2 - methyl pentane                  2) 2, 2 dimethyl butane
3) 2, 3 di methyl butane             4) n - Hexane
Ans: (3)
Explanation: 
 

      
19. Elimination of bromine from 2 - bromobutane results
1) predominantly 2 - butene             2) predominantly 2 - butyne
3) predominantly 1 - butene            4) equimolar mixture of 1 - & 2 - butene
Ans: (1)
Explanation:

20. The compound that can yield acetone and acetaldehyde on ozonolysis is
1) cyclopentane                            2) 3 - methyl - 1 - butene
3) 2 - methyl - 1 - butene            4) 2 - methyl - 2 - butene
Ans: (4)
Explanation:

 

21. 2, 2 dibromopropane will be given by the reaction
1) HC ≡ CH + 2 HBr               2) H3CCH = CHBr + HBr
3) H3C - C ≡ CH                    4) H3C - CH = CH2 + HBr
Ans: (3)
Explanation: According to Markownikoff’s addition

22. During chlorination of methane to methyl chloride, the propagation step is represented by
1)                          2)  
3)                 4) 
Ans: (2)
Explanation:

 

23. The following compound(s) cause(s) cancer due to damage of DNA is/ are
1) 9, 10 - Dimethyl 1, 2 - benzanthracene         2) 1, 2, 5, 6 - Dibenzanthracene
3) 1, 2 - Benzpyrene                                          4) all the above
Ans: (4)
Explanation: all the 3 compounds are Carcinogenic.

 

24. Number of moles of O2 required for complete combustion of any hydrocarbon CxHy is

Ans: (1)
Explanation:

 

25. 2 - methylpropene when treated with acidified KMnO4 gives
1) butanoic acid          2) propan - 2 - one        3) butan - 2 - one        4) butan 1, 4 diol
Ans: (2)
Explanation:

 

 

1) Chain isomers   2) Optical isomers   3) Geometrical isomers  4) Position isomers
Ans: (3)
Explanation:

 

27. Pyrolysis of C6H14 at 773 K gives
1) CH4, C2H4, C3H6         2) C4H8          3) C6H12, C2H6          4) all the above
Ans: (4)
Explanation:

Higher alkanes on Pyrolysis gives lower alkanes & alkenes.
 

28. n - Hexane on treatment with anhydrous AlCl3 & HCl gives
1) 2 - methyl pentane & 3 - methyl pentane         2) only 2 - methyl pentane
3) 3, 3 dimethyl butane                                         4) benzene
Ans: (1)
Explanation:

 

29. Methane can not be prepared by
1) Decarboxylation of sodium methanoate with soda lime
2) Wurtz reaction           3) Kolbe’s electrolytic method          4) all the above
Ans: (4)
Explanation: decarboxylation of sodium ethanoate give methane. Wurtz reaction gives ethane & higher alkanes only. Kolbe’s electrolysis gives ethane & higher alkanes only.

 

30. Incorrect statement among the following is
1) Magnitude of torsional strain depends upon dihedral angle.
2) The energy difference between 2 forms of conformers of ethane is of the order of 12.5 KJ mol-1.
3) It is easy to separate and isolate different conformational isomers of ethane.
4) Eclipsed conformers of ethane are possible at 120°, 240° and 360° whereas staggered conformers of ethane are possible at dihedral angles 60° , 180° and 300°.
Ans: (3)
Explanation: It is not possible to separate and isolate different conformational isomers of ethane.

Posted Date : 27-08-2021

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