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Free download in PDF Class 12 Chemistry Chapter 7 p Block Elements Short Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams like NEET, AIIMS, JIPMER etc. These short solved questions or quizzes are provided by Gkseries./p>
(1)
An aqueous solution of borax is
[A]
neutral
[B]
acidic
[C]
basic
[D]
none
(2)
Crystalline metal can be transformed into metallic glass by
[A]
Alloying
[B]
Pressing into thin plates
[C]
Slow cooling of molten metal
[D]
Very rapid cooling of the molten metal
Answer: Very rapid cooling of the molten metal
(3)
Which metal is protected by a layer of it own oxide
[A]
Al
[B]
Ag
[C]
Au
[D]
Fe
(4)
B(OH)3 + NaOH → NaBO2+Na[B(OH)4] +H2O How can this reaction is made to proceed in forward direction.
[A]
Addition of cis Benzene - 1,2-diol
[B]
Addition of Borax
[C]
Addition of trans-Benzene 1,2-diol
[D]
Addition of Na2HPO4
Answer: Addition of cis Benzene - 1,2-diol
(5)
An element A dissolves both in acid and alkali. It is an example of
[A]
Allotropie nature of A
[B]
Dimorphic nature of A
[C]
Amorphous nature of A
[D]
Amphoteric nature of A
Answer: Amphoteric nature of A
(6)
Which among the following is not a borane
[A]
B2H6
[B]
B3H6
[C]
B4H10
[D]
None of these
(7)
In Goldschmidt aluminothermic process, thermite contains
[A]
3 parts of Al2O3 and 4 Parts of Al
[B]
3 parts of Fe2O3 and 2 parts of Al
[C]
3 Parts of Fe2O3 and 1 part of Al
[D]
1 Part of Fe2O3 and 1 Part of Al
Answer: 3 Parts of Fe2O3 and 1 part of Al
(8)
Aluminium oxide is not reduced by chemical reactions since
[A]
Aluminium oxide is reative
[B]
Reducing agents contaminate
[C]
Aluminium oxide is highly stable
[D]
The process pollutes the environment
Answer: Aluminium oxide is highly stable
(9)
Aluminium is not used
[A]
In silvery paints
[B]
For making utensils
[C]
As a reducing agent
[D]
As oxidizer in metalurgy
Answer: As oxidizer in metalurgy
(10)
Bauxite containing impurities of iron oxide is purified by
[A]
Hoop’s Process
[B]
Serpeck’s Process
[C]
Bayer’s Process
[D]
Electrolytic process
(11)
In the purification of Bauxite by Hall’s process
[A]
Bauxite ore is heated with NaOH solution at 50°C
[B]
Bauxite ore is heated with NaHCO3
[C]
Bauxite ore is fused with coke and heated at 1800°C in a current of nitrogen
[D]
Bauxite ore is heated with NaHCO3
Answer: Bauxite ore is heated with NaHCO3
(12)
The type of hybridization of boron in diborane is
[A]
Sp- hybridization
[B]
Sp2 - hybridization
[C]
Sp3 - hybridization
[D]
Sp3d2 - hybridization
Answer: Sp3 - hybridization
(13)
Identify the statement that is not correct as far as structure of diborane is concerned.
[A]
There are two bridging hydrogen atoms in diborane
[B]
Each boron atom forms four bonds in diborane
[C]
The hydrogen atoms are not in the same plane in diborane
[D]
All B-H bonds in diborane are similar
Answer: All B-H bonds in diborane are similar
(14)
Soft heavy metal melts at 30°C and is used in making heat sensitive thermometers, the metal is
[A]
Gallium
[B]
Sodium
[C]
Potassium
[D]
cesium
(15)
In the reaction B2O3 + C + Cl2 → A + CO . The A is
[A]
BCl3
[B]
BCl2
[C]
B2Cl2
[D]
CCl2
(16)
The most acidic of the following compound is
[A]
P2O3
[B]
Sb2O3
[C]
B2O3
[D]
As2O3
(17)
Heating an aqeous solution of aluminium chloride to dryness will give
[A]
AlCl3
[B]
Al2Cl6
[C]
Al2O3
[D]
Al(OH)Cl2
(18)
Which of the following is the electron deficient molecule
[A]
B2H6
[B]
C2H6
[C]
PH3
[D]
SiH4
(19)
The structure of diborane Contains
[A]
Four 2c - 2e bonds and two 3c - 2e bonds
[B]
Two 2c - 2e bonds and Four 3c - 2e bonds
[C]
Two 2c - 2e bonds and two 3c - 3e bonds
[D]
Four 2c - 2e bonds and four 3c - 2e bonds
Answer: Four 2c - 2e bonds and two 3c - 2e bonds
(20)
In Hall Heroult's process, the main reagent is mixed with
[A]
B2 H6
[B]
C2 H6
[C]
Na3AlF6
[D]
SiH4
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