Covalent Bonding & Lewis Structures — Practice Questions

Free NEET Chemistry multiple-choice questions on Covalent Bonding & Lewis Structures. Attempt each question and reveal the answer with a full explanation.

In the carbonate ion ( CO 3 2- ), the C-O bond lengths are: All equal Two equal and one different All three different Related to the size of the cation What is the formal charge on the Oxygen atom in the hydroxide ion ( OH - )? -1 0 +1 -2 In the ozone molecule ( O 3 ), the O-O bond lengths are: Identical due to resonance Different because one is a double bond and one is single Constantly changing due to vibration Equal to the O-O bond length in O 2 The total number of σ and π bonds in the ethylene ( C 2H 4 ) molecule is: 5 σ and 1 π 4 σ and 1 π 3 σ and 2 π 2 σ and 2 π Which of the following is an example of a molecule where the central atom has an incomplete octet? BeH 2 PCl 3 SF 6 NF 3 The bond length of C-C bond in benzene is: Intermediate between C-C and C=C Same as in C 2H 6 Same as in C 2H 4 Same as in C 2H 2 Which of the following is the electron deficient molecule - C2H6 SiH4 PH3 B2H6 [ NH(CH2)NHCO(CH2)4CO ] n is a:- copolymer Addition polymer Thermosetting polymer Homopolymer Which one of the following polymers is prepared by condensation polymerisation? Teflon Natural rubber Styrene Nylon-66 Which of the following molecules acts as a Lewis acid ? ( CH 3 ) 3 N ( CH 3 ) 3 B ( CH 3 ) 2 O ( CH 3 ) 3 P Which of these is least likely to act as a Lewis base? CO F - BF3 PF3 The bond in NH 4 + formed between NH 3 and H + is a: Coordinate covalent bond Ionic bond Metallic bond Hydrogen bond Which one of the following molecules contains no bond? CO2 H2O SO2 NO2 Nylon is an example of Polyester Polysaccharide Polyamide Polythene Which one of the following polymers is prepared by addition polymerisation? Nylon-66 Novolac Dacron Teflon Amongst the following the total number of species NOT having eight electrons around central atom in its outermost shell, is NH3 , AlCl3 , BeCl2 , CCl4 , PCl5 : 3 2 4 1 The number of bonds, bonds and lone pair of electrons in pyridine, respectively are: 11, 2, 0 12, 3, 0 11, 3, 1 12, 2, 1 Amongst the given options which of the following molecules/ ion acts as a Lewis acid? NH3 H2O BF3 OH- Match List I with List II : array llll ; & List I & ; & List II A. & C2H4 & I. & 3 bonds, 2 bonds B. & C2H2 & II. & 3 bonds, one lone pair C. & CH4 & III. & 4 bonds D. & NH3 & IV. & 5 bonds, 1 bond array Choose the correct answer from the options given below : A-IV, B-I, C-III, D-II A-III, B-IV, C-II, D-I A-II, B-III, C-I, D-IV A-I, B-II, C-IV, D-III What is the formal charge on the sulfur atom in the sulfate ion ( SO 4 2- ) if all S-O bonds are shown as single bonds in the Lewis structure? +2 0 +1 -2 The formal charge on the central nitrogen atom in the azide ion ( N 3 - ), for the most stable resonance structure ( [N=N=N] - ), is: +1 -1 0 +2 The B-F bond length in BF 3 is shorter than that in BF 4 - because of: p -p back bonding in BF 3 sp 2 hybridization in BF 4 - sp 3 hybridization in BF 3 Stronger repulsion in BF 3 Which of the following molecules violates the octet rule by having an expanded octet? PCl 5 CH 4 NH 3 H 2O The number of σ and π bonds in tetracyanoethylene, C 2(CN) 4 , are respectively: 9 σ and 9 π 5 σ and 9 π 9 σ and 7 π 5 σ and 8 π The bond lengths of H 2 and D 2 are observed to be: Exactly the same H 2 > D 2 D 2 > H 2 Cannot be determined What is the formal charge on the central Chlorine atom in the perchlorate ion ( ClO 4 - ) if the Lewis structure is drawn with only single bonds? +3 +7 +1 0 The correct order of Lewis acid strength for Boron halides is: BI 3 > BBr 3 > BCl 3 > BF 3 BF 3 > BCl 3 > BBr 3 > BI 3 BCl 3 > BF 3 > BBr 3 > BI 3 BBr 3 > BCl 3 > BI 3 > BF 3 What is the formal charge on the Nitrogen atom in the nitrite ion ( NO 2 - ) in its most stable Lewis structure? 0 +1 -1 +2 What is the formal charge on the Chlorine atom in the perchlorate ion ( ClO 4 - ) if the structure is drawn to satisfy the octet rule for all Oxygen atoms using only single bonds? +3 +1 +7 0 What is the formal charge on the Nitrogen atom in the Nitrate ion ( NO 3 - ) based on the standard Lewis structure? +1 0 -1 +5 The formal charge on the Chlorine atom in the chlorite ion ( ClO 2 - ), assuming a Lewis structure that obeys the octet rule for all atoms, is: +1 0 +3 +5 Which of the following is electron-deficient? (BH 3) 2 PH 3 (CH 3) 2 SiH 4 The formal charge on the central oxygen atom in the ozone ( O 3 ) molecule is: +1 0 +2 −1 Which of the following molecules has the shortest C-C bond length? C 2H 2 C 2H 4 C 2H 6 C 6H 6 Which one of the following is an example of a thermosetting polymer? Which of the following statements is incorrect? Of - O -C + O , O=C=O , the structures, - O -C + O is most stable structure The bond angle follows the order CH4 > NH3 > H2O > H2S The bond order follows the order O2 + > O2 > O2 - > O2 2- Strength of ‘H’ bond follows the order HF > H2O > NH3 > HCl Match List-I with List-II. array ll List – I (Hydrides) & List – II (Nature) (a) MgH2 & (i) Electron precise (b) GeH4 & (ii) Electron deficient (c) B2H6 & (iii) Electron rich (d) HF & (iv) Ionic array Choose the correct answer from the options given below (a) – (iii), (b) – (i), (c) – (ii), (d) – (iv) (a) – (i), (b) – (ii), (c) – (iv), (d) – (iii) (a) – (ii), (b) – (iii), (c) – (iv), (d) – (i) (a) – (iv), (b) – (i), (c) – (ii), (d) – (iii) Match List I with List II. array ll List I (Molecule) & List II (Number and types of bond/s between two carbon atoms) A. ethane & I. one -bond and two -bonds B. ethene & II. two -bonds C. carbon molecule, C2 & III. one -bond D. ethyne & IV. one -bond and one -bond array Choose the correct answer from the options given below: A-I, B-IV, C-II, D-III A-IV, B-III, C-II, D-I A-III, B-IV, C-II, D-I A-III, B-IV, C-I, D-II Identify the correct answer. Three resonance structures can be drawn for ozone BF3 has non-zero dipole moment Dipole moment of NF3 is greater than that of NH3 Three canonical forms can be drawn for CO3 2- ion Among the given compounds I-III, the correct order of bond dissociation energy of C-H bond marked with is : II > III > I II > I > III I > II > III III > II > I The correct formal charges on oxygen atoms numbered 2, 1 and 3 respectively are : 0, 0, 0 -1, 0, +1 +1, 0, -1 0, +1 , -1 Which of the following resonance structures of Nitrous oxide ( N 2O ) correctly accounts for its small dipole moment? :N N + - O: - :N - = N + = O: :N + = N - O -: :N - N O +: The number of bonds in the molecule N 2O 3 (dinitrogen trioxide) is: 2 1 3 4 The straight chain polymer is formed by – hydrolysis of ( CH 3 ) 2 SiCl 2 followed by condensation polymerization hydrolysis of ( CH 3 ) 3 SiCl followed by condensation polymerization hydrolysis of CH 3SiCl 3 followed by condensation polymerization hydrolysis of ( CH 3 ) 4 Si by addition polymerization Which of the following compounds contains a coordinate covalent bond? O 3 H 2O NaCl NH 3 Which of the following is an example of an odd-electron molecule? NO 2 CO 2 SO 2 N 2O Which of the following is NOT an exception to the octet rule? CO 2 NO BeCl 2 ClF 3 The formal charge on the Nitrogen atom in the Ammonium ion ( NH 4 + ) is: +1 0 -1 +5 What is the formal charge on the Chlorine atom in the hypochlorite ion ( ClO - )? 0 -1 +1 +2