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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The B–F bond lengths in BF3 (130 pm) and BF4-(143 pm) differ because of:

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 sharp decrease in ionization enthalpy from carbon to silicon happens because of-

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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Incorrect statement among the following options is :

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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BCl has higher stability than TlCl3, because -

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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The correct explanation for the lower atomic radius of Ga as compared to Al is -

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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