Class 12 Chemistry Chapter 7 p Block Elements MCQs | Class 12 Chemistry Chapter 7 p Block Elements Short Questions and Answers

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Questions
1 An aqueous solution of borax is
A neutral
B acidic
C basic
D none

Answer:basic
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

Answer:Al
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

Answer: B3H6
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

Answer: Bayer’s 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

Answer:Gallium
15 In the reaction B2O3 + C + Cl2 → A + CO . The A is
A BCl3
B BCl2
C B2Cl2
D CCl2

Answer:BCl3
16 The most acidic of the following compound is
A P2O3
B Sb2O3
C B2O3
D As2O3

Answer:B2O3
17 Heating an aqeous solution of aluminium chloride to dryness will give
A AlCl3
B Al2Cl6
C Al2O3
D Al(OH)Cl2

Answer:Al2O3
18 Which of the following is the electron deficient molecule
A B2H6
B C2H6
C PH3
D SiH4

Answer:B2H6
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

Answer:Na3AlF6

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