CBSE Class 11 Chemistry The p Block Elements Assignment

The P Block Elements MCQ Questions with Answers Class 11 Chemistry

Question- When Al is added to KOH solution

(a) no action takes place

(b) oxygen is evolved

(c) water is produced

(d) hydrogen is evolved

Answer-(d)

Question- H₃BO₃ on heating up to 373 K yields:

(a) boric anhydride

(b) orthoboric acid

(c) metaboric acid

(d) tetraboric acid

Answer-(c)

Question-Amphoteric oxide among the following is

(a) B₂O₃

(b) Ga₂O₃

(c) In₂O₃

(d) Tl₂O₃

Answer-(b)

Question- NH₃ and BF₃ form an adduct readily because they form

(a) a coordinate bond

(b) a hydrogen bond

(c) an ionic bond

(d) a covalent bond

Answer-(a)

Question-Which is false in case of boric acid H₃BO₃?

(a) It acts as a tribasic acid.

(b) It has a planar structure.

(c) It acts as a monobasic acid.

(d) It is soluble in hot water.

Answer-(a)

Question- In borax bead test which compound is formed?

(a) Ortho-borate

(b) Meta-borate

(c) Double oxide

(d) Tetra-borate

Answer-(b)

Question-Diborane upon hydrolysis gives

(a) boric anhydride

(b) metaboric acid

(c) orthoboric acid

(d) boron oxide

Answer-(c)

Question- B(OH)₃ is

(a) monobasic acid

(b) dibasic acid

(c) tribasic acid

(d) triacidic base

Answer-(a)

Question-Which of the following does not react with aqueous NaOH ?

(a) B

(b) Al

(c) Ga

(d) Tl

Answer-(a)

Question-Orthoboric acid when heated to red hot gives

(a) metaboric acid

(b) pyroboric acid

(c) boron and water

(d) boric anhydride

Answer-(b)

Question-The structure of diborane ( B₂H₆ ) contains

(a) four 2c-2e bonds and four 3c-2e bonds

(b) two 2c-2e bonds and two 3c-3e bonds

(c) two 2c-2e bonds and four 3c-2e bonds

(d) four 2c-2e bonds and two 3c-2e bonds

Answer-(d)

Question-In diborane

(a) 4–bridged hydrogens and two terminal hydrogens are present

(b) 2– bridged hydrogens and four terminal hydrogens are present

(c) 3–bridged and three terminal hydrogens are present

(d) None of these

Answer-(b)

Question-Boron forms covalent compound due to

(a) higher ionization energy

(b) lower ionization energy

(c) small size

(d) Both (a) and (c)

Answer-(d)

Question-Boric acid is polymeric due to

(a) its acidic nature

(b) the presence of hydrogen bonds

(c) its monobasic nature

(d) its geometry

Answer-(b)

Question-Borazole is known as

(a) organic benzene

(b) organic xylene

(c) inorganic benzene

(d) inorganic xylene

Answer-(c)

Question-The compounds of boron and hydrogen are collectively called

(a) diboranes

(b) borazoles

(c) boracits

(d) boranes

Answer-(d)

Question- The two type of bonds present in B2H6 are covalent and

(a) ionic

(b) co-ordinate

(c) hydrogen bridge bond

(d) None of these

Answer-(c)

More Question

ONE MARK QUESTIONS

1 Give the method of preparation of LiBH₄

2 What is inert pair effect?

3 Give reasons for the following. 

a) There is gradual increase in electro negativity from Al to Tl.

b) Boron does not form [BF₆]^3- ion..

c) PbCl₄ decomposes easily on heating.

d) Al is used in making alloys for aircraft industry.

e) Si does not form graphite like structure.

f) Fullerenes are the purest forms of carbon.

g) CCl₄ cannot be hydrolysed.

h) CO is highly poisonous.

TWO MARKS QUESTIONS

1. Compare the structure of SiO₂ and CO₂.

2. How are silicones prepared? Give its twouses.

3. Explain why

a) BCl₃ is more stable than TlCl₃.

b) PbI₄ does not exist

4. Is boric acid a protic acid ? Explain.

5 Explain why CO₂ is a gas whereas SiO₂ is a solid?

THREE MARKS QUESTIONS

1 Describe with suitable examples:
a) Zeolites
b) Metal carbonyl
c) allotropes

2 What happens when?
b) Borax is dehydrated
c) Boric acid is heated

3 A salt A, gives the following results :
a. It aqueous solution is alkaline to litmus
b. It swells up to a glassy material B on strong heating.
When conc. H₂SO₄ is added to a hot solution of A, white crystals an acid C separates out. Write equations for all the above reactions and identify A, B and C.

4 Complete the following chemical equations:
a) + 3 LiAlH₄→ + 3LiF + 3 AlF₃
b) B₂H₆ + H₂O →
c) Al + NaOH + H₂O →

5 Give two uses of:
a) Boron fibre
b) Carbon-14
c) Quartz

6 Explain the structures of:
a) Boric acid
b) Fullerene
c) Diborane