ORGANIC CHEMISTRY - SOME BASIC PRINCIPLES AND TECHNIQUES Quiz-17

Organic chemistry - some basic principles and techniques Quiz-17

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Q1.The increasing order of pK_b value of the following is:

•   IV< III< II< I
•  I< II< III< IV
•  IV< II< III< I
•  I< III< II< IV

Solution

Q2.The enolic form of acetone contains:

•  9 σ-bonds, 1 π-bond, and 2 lone pairs
•  8 σ-bonds, 2 π-bond, and 2 lone pairs
•  10 σ-bonds, 1 π-bond, and 1 lone pair
•  9 σ-bonds, 2 π-bonds, and 1 lone pair

Solution

Q3. A compound whose molecule is superimposable on its mirror image despite containing chiral carbon atoms is called:

•  Threo isomer
•  Meso compound
•  Enantiomer
•  No special name

Solution
Although the meso compounds contain asymmetric C atoms, but they are optically inactive due to superimposable mirror image or due to the presence of any element of symmetry

Q4. Which of the following is zerone?

•  MeOH
•  
•  
•  EtOH

Solution
CH_3 OH is also called zerone

Q5. Which group is always taken as a substituent in the IUPAC system of nomenclature?

•  -NO_2
•  -C≡N
•  
•  -NH_2

Solution
 

Self-Explainatory

Q6. Which of the following hydrocarbons has the lowest dipole moment?

•  
•  CH_3 C≡CCH_3
• CH_3 CH_2 C≡CH
•  CH_3 CH_2 C≡CH

Solution
CH_3 C≡CCH_3 is linear and symmetrical and thus dipole moment is zero

Q7. In organic layer test, CS_2 or CCl_4 is added to Lassaigne's extract and then Cl_2 water or KMnO_4 is added. This test is used to distinguish between

•  Br^⊖ andI^⊝
•  Cl^⊝ andBr^⊝
•  Cl^⊝ and I^⊝
•  Cl^⊝ and I^⊝

Solution
distinguish between Br^⊝andI^⊖;

Q8. Which of the following sodium compound is/are formed when an organic compound containing both nitrogen and sulphur is fused with sodium?

•  Sulphite and cyanide
•  Thiocyanate
•  Cyanide and Sulphide
•  Nitrate and Sulphide

Solution

Na reacts with C, N, and S to form NaCNS (sodium thiocyanate)

Q9. Which of the following is not a cumulated diene?

•  Hexa-1,2-diene
•  Hexa-2,3-diene
•  Penta-2,3-diene
•  Penta-1,3-diene

Solution

Q10. The Prussian blue colour obtained during the test of nitrogen by Lassaigne's test is due to the formation of:

•  Fe_4 [Fe(CN)_6 ]_3
•  Fe_2 [Fe(CN)_6]
•  Fe_3 [Fe(CN)_6 ]_4
• Na_4 [Fe(CN)_6]

Solution
Fe^(3+)+〖[Fe(CN)₆]〗^(4-)→ Fe_4 [Fe(CN)_6 ]_3 Prussian blue (Ferri-ferrocyanide)