P Block Elements(12th Grade > Chemistry ) Questions and answers for exam Preparation

12th Grade > Chemistry

P BLOCK ELEMENTS MCQs

Total Questions : 30 | Page 3 of 3 pages

Question 21. Which of the following reaction can produce boron nitride 'BN'

BCl3+(C2H5)+NC−ICHCl3−−−−→?
NH4Cl+Na2B4O7RedHot−−−−→
BCl3+NH4Cl140∘C−−−−→C6H5Cl?NaBHa−−−−−→
All the above

Discuss Question

Answer: Option B. -> NH4Cl+Na2B4O7RedHot−−−−→
:
B

2 N H_{4} C l + N a_{2} B_{4} O_{7} Δ - \to 2 B N + B_{2} O_{3} + 2 N a C l + 4 H_{2} O

Question 22. Name of the structure of silicates in which three oxygen atoms of

[S i O_{4}]^{4 -}

are shared -

Pyrosilicate
Sheet silicate
Linear chain silicate
Three dimensional silcate

Discuss Question

Answer: Option B. -> Sheet silicate
:
B
(i) In such silicates, three oxygen atoms of each tetrahedra are shared with adjacent

S i O_{4}^{4 -}

tetrahedra.
(ii) such sharing forms two dimensional sheet structure with general formulae

(S i_{2} O_{5})_{2}^{2 -}

as shown below

Name Of The Structure Of Silicates In Which Three Oxygen Ato...

Question 23. Which one of the following statements is not true regarding diborane?

It has two bridging hydrogenes and four perpendicular to the rest
When methylated, the product is Me4B2H2
The bridging hydrogenes are in a plane perpendicular to the rest.
All the B-H bond distances are equal.

Discuss Question

Answer: Option D. -> All the B-H bond distances are equal.
:
D
Two hydrogens out of 6 have different bond length

Which One Of The Following Statements Is Not True Regarding ...

Question 24. Which one of the following mixed sulphates is not an alum ?

K2SO4.Al2(SO4)3.24H2O
K2SO4.Cr2(SO4)3.24H2O
Na2SO4.Fe2(SO4)3.24H2O
CuSO4.Al2(SO4)3.24H2O

Discuss Question

Answer: Option D. -> CuSO4.Al2(SO4)3.24H2O
:
D
Alums contain monovalent

M^{+}

and trivalent

M^{+ 3}

ions

C u S O_{4} . A l_{2} (S O_{4})_{3} .24 H_{2} O

has

C u^{+ 2}

and

A l^{+ 3}

ions

Question 25. Which one of the following statements about

H_{3} B O_{3}

is not correct ?

It is a tribasic acid
It is prepared by acidifying an aqueous solution of borax
It has a layer structure in which planar BO3 units are joined by hydrogen bonds
It does not act as proton donor as it acts as a Lewis acid by accepting hydroxyl ion

Discuss Question

Answer: Option A. -> It is a tribasic acid
:
A

H_{3} B O_{3}

is weak monobasic acid

Question 26. An inorganic compound (A) is made of two most occuring elements in the Earth's crust and has a polymeric tetrahedral network structure. With carbon, compound (A) produces a poisonous gas (B) which is the most stable diatomic molecule. Compounds (A) and (B) will be

SiO2,CO2
SiO2,CO
SiC,CO
SiO2,N2

Discuss Question

Answer: Option B. -> SiO2,CO
:
B

S i O_{2} + 2 C \to S i + 2 C O

Question 27. Borax is actually made of two tetrahedra and two triangular units joined together and should be written as: Na2[B4O5(OH)4]·8H2O
The correct statement/s about borax is/are:
a. Each boron atom has four B-O bonds
b. Each boron atom has three B-O bonds
c. Two boron atoms have four B-O bonds while other two have three B-O bonds
d. Each boron atom has one -OH groups

Discuss Question

Answer: Option B. -> b
:
B