p-Block Elements-Assertion & Reason Questions for Class 12 Chemistry

Directions: These questions consist of two statements, each printed as Assertion and Reason. While answering these questions, you are required to choose any one of the following four responses.
(a) Assertion is correct, reason is correct; reason is a correct explanation for assertion.
(b) Assertion is correct, reason is correct; reason is not a correct explanation for assertion
(c) Assertion is correct, reason is incorrect
(d) Assertion is incorrect, reason is correct.

Q.1. Assertion : Dinitrogen is inert at room temperature.
Reason : Dinitrogen directly combines with lithium to form ionic nitrides. Answer

(c)


Q.2. Assertion : N2 is less reactive than P4.
Reason : Nitrogen has more electron gain enthalpy than phosphorus. Answer

(c)


Q.3. Assertion : When a metal is treated with conc. HNO3 it generally yields a nitrate, NO2 and H2O.
Reason : Conc. HNO3 reacts with metal and first produces a metal nitrate and nascent hydrogen. The nascent hydrogen then further reduces HNO3 to NO2 Answer

(a)


Q.4. Assertion : White phosphorus is more reactive than red phosphorus.
Reason : Red phosphorus consists of P4 tetrahedral units linked to one another to form linear chains. Answer

(b) White phosphorus exists as P4 tetrahedral molecule
having P-P-P bond angle 60º. Hence the molecule is
under strain and more reactive. On the other hand red
phosphorus exists as P4 tetrahedra which are joined
together through covalent bonds giving polymeric
structure.


Q.5. Assertion : Bond angle of H2S is smaller than H2O.
Reason : Electronegativity of the central atom increases, bond angle decreases. Answer

(c)


Q.6. Assertion : Both rhombic and monoclinic sulphur exist as S8 but oxygen exists as O2.
Reason : Oxygen forms pπ – pπ multiple bond due to small size and small bond length but pπ – pπ bonding is not possible in sulphur. Answer

(a)


Q.7. Assertion : SF6 cannot be hydrolysed but SF4 can be.
Reason : Six F atoms in SF6 prevent the attack of H2O on sulphur atom of SF6. Answer

(a)


Q.8. Assertion: Ozone is thermodynamically stable with respect to oxygen.
Reason: Decomposition of ozone into oxygen results in the liberation of heat Answer

(d)


Q.9. Assertion : Inert gases are monoatomic,
Reason : Inert gases have stable configuration. Answer

(a)


Q.10. Assertion : Fluorine exists only in-1 oxidation state.
Reason: Fluorine has 2s22p5 configuration. Answer

(a)


Q.11. Assertion : The fluorine has lower reactivity.
Reason : F-F bond has low bond dissociation energy. Answer

(c)


Q.12. Assertion: F-F bond in F2 molecule is weak.
Reason: F atom is small in size. Answer

(a)


Er. Neeraj K.Anand is a freelance mentor and writer who specializes in Engineering & Science subjects. Neeraj Anand received a B.Tech degree in Electronics and Communication Engineering from N.I.T Warangal & M.Tech Post Graduation from IETE, New Delhi. He has over 30 years of teaching experience and serves as the Head of Department of ANAND CLASSES. He concentrated all his energy and experiences in academics and subsequently grew up as one of the best mentors in the country for students aspiring for success in competitive examinations. In parallel, he started a Technical Publication "ANAND TECHNICAL PUBLISHERS" in 2002 and Educational Newspaper "NATIONAL EDUCATION NEWS" in 2014 at Jalandhar. Now he is a Director of leading publication "ANAND TECHNICAL PUBLISHERS", "ANAND CLASSES" and "NATIONAL EDUCATION NEWS". He has published more than hundred books in the field of Physics, Mathematics, Computers and Information Technology. Besides this he has written many books to help students prepare for IIT-JEE and AIPMT entrance exams. He is an executive member of the IEEE (Institute of Electrical & Electronics Engineers. USA) and honorary member of many Indian scientific societies such as Institution of Electronics & Telecommunication Engineers, Aeronautical Society of India, Bioinformatics Institute of India, Institution of Engineers. He has got award from American Biographical Institute Board of International Research in the year 2005.