The effect of heating Boric acid at 370 K or above is :

1. Orthoboric acid changes to metaboric acid.

2. Metaboric acid changes to boric oxide.

3. Both '1' and '2'

4. Neither '1' nor '2'

Subtopic:  Compounds of Boron- Preparations, Properties & Uses |
 68%
Level 2: 60%+
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Why is the B–F bond length in BF₃ (130 pm) shorter than that in BF₄⁻ (143 pm)?

1. Presence of triple-bond character in BF3

2. Resonance in BF4-

3. Presence of a double-bond character in BF3

4. Presence of a double bond character in BF4-

Subtopic:  Compounds of Boron- Preparations, Properties & Uses |
 54%
Level 3: 35%-60%
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The first ionization enthalpy decreases sharply from carbon to silicon in Group 14. What is the main reason for this decrease?

1. Decrease in the charge of elements upon moving down the group.
2. Decrease in the atomic sizes of elements upon moving down the group.
3. Increase in the atomic sizes of elements upon moving down the group.
4. Increase in the charge of elements upon moving down the group.

Subtopic:  Carbon Family - Preparations, Properties & Uses |
 84%
Level 1: 80%+
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The correct statement(s) regarding diborane and boric acid is/are :

1. Diborane has two 3c-2e- bonds.

2. Boric acid has a layered structure.

3. Four 2c-2e- bonds are present in diborane.

4. All of the above

Subtopic:  Compounds of Boron- Preparations, Properties & Uses |
 88%
Level 1: 80%+
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Which of the following statements is incorrect?

1. Tl (+1) is more stable than Tl (+3).
2. For group 13, the stability of the +3 oxidation state decreases down the group.
3. Ge, Sn, and Pb show both the +2 and + 4 states.
4. None of the above.

Subtopic:  Boron Family- Preparations, Properties & Uses | Carbon Family - Preparations, Properties & Uses |
 68%
Level 2: 60%+
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Why is BCl₃ more stable than TlCl₃?

1. The +2 oxidation state of Tl is more stable than the +2 oxidation state of B
2. The +2 oxidation state of B is more stable than the +2 oxidation state of Tl
3. The +3 oxidation state of B is more stable than the +3 oxidation state of Tl
4. The +3 oxidation state of Tl is more stable than the +3 oxidation state of B

Subtopic:  Compounds of Boron- Preparations, Properties & Uses |
 86%
Level 1: 80%+
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The electron-deficient compound among the following is -

1. SiCl4

2. BCl3

3. PCl3

4. ICl

Subtopic:  Compounds of Boron- Preparations, Properties & Uses |
 91%
Level 1: 80%+
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Despite the dipole moment in the B–Cl bond, the BCl3 molecule as a whole has no dipole moment because:

1. The respective dipole-moments of the B–Cl bond add with each other
2. The respective dipole moments of the B–Cl bond cancel each other
3. BCl3 is tetrahedral in shape
4. None of the above

Subtopic:  Compounds of Boron- Preparations, Properties & Uses |
 85%
Level 1: 80%+
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Which of the following best explains why the atomic radius of gallium is smaller than that of aluminium?

1. Poor shielding effect of the 2d-electrons

2. Poor shielding effect of the 3d-electrons

3. Poor shielding effect of the 3p-electrons

4. Poor shielding effect of the 2s-electrons

Subtopic:  Boron Family- Preparations, Properties & Uses |
 87%
Level 1: 80%+
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The correct reaction(s) among the following options is/are -

1. SiO2 + 4HF → SiF4 + 2H2O

2. ZnO + CO → Zn + CO2

3. SiF4  + 2HF → H2SiF6

4. All of the above

Subtopic:  Compounds of Carbon, Preparations, Properties & Uses |
 89%
Level 1: 80%+
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