Boron and its Compounds
CHXI11:THE P-BLOCK ELEMENTS

316070 When boron is heated strongly with graphite, it forms

1 \({{\rm{B}}_{{\rm{12}}}}{{\rm{C}}_{\rm{3}}}{\rm{(s)}}\)
2 \(\mathrm{BC}(\mathrm{s})\)
3 \(\mathrm{B}_{2}\left(\mathrm{CO}_{3}\right)_{2}\)
4 \(\mathrm{B}_{2} \mathrm{H}_{6}\)
CHXI11:THE P-BLOCK ELEMENTS

316071 How many moles of \({\mathrm{\mathrm{NO}_{2}}}\) are produced when mole of B reacts with \({\mathrm{\mathrm{HNO}_{3}}}\) ?

1 5
2 4
3 3
4 8
CHXI11:THE P-BLOCK ELEMENTS

316072 Boron has an extremely high melting point because of

1 The strong van der Waal's forces between its atoms
2 The strong binding forces in the covalent polymer
3 Its ionic crystal structure
4 Allotropy
CHXI11:THE P-BLOCK ELEMENTS

316073 Consider the given statements regarding the properties of boron.
I. It is a hard refractory solid.
II. It has low melting point and high density.
III. It shows high electrical conductivity
Choose the correct statement(s).

1 Only I
2 I and III
3 Both II and III
4 All are correct
CHXI11:THE P-BLOCK ELEMENTS

316070 When boron is heated strongly with graphite, it forms

1 \({{\rm{B}}_{{\rm{12}}}}{{\rm{C}}_{\rm{3}}}{\rm{(s)}}\)
2 \(\mathrm{BC}(\mathrm{s})\)
3 \(\mathrm{B}_{2}\left(\mathrm{CO}_{3}\right)_{2}\)
4 \(\mathrm{B}_{2} \mathrm{H}_{6}\)
CHXI11:THE P-BLOCK ELEMENTS

316071 How many moles of \({\mathrm{\mathrm{NO}_{2}}}\) are produced when mole of B reacts with \({\mathrm{\mathrm{HNO}_{3}}}\) ?

1 5
2 4
3 3
4 8
CHXI11:THE P-BLOCK ELEMENTS

316072 Boron has an extremely high melting point because of

1 The strong van der Waal's forces between its atoms
2 The strong binding forces in the covalent polymer
3 Its ionic crystal structure
4 Allotropy
CHXI11:THE P-BLOCK ELEMENTS

316073 Consider the given statements regarding the properties of boron.
I. It is a hard refractory solid.
II. It has low melting point and high density.
III. It shows high electrical conductivity
Choose the correct statement(s).

1 Only I
2 I and III
3 Both II and III
4 All are correct
CHXI11:THE P-BLOCK ELEMENTS

316070 When boron is heated strongly with graphite, it forms

1 \({{\rm{B}}_{{\rm{12}}}}{{\rm{C}}_{\rm{3}}}{\rm{(s)}}\)
2 \(\mathrm{BC}(\mathrm{s})\)
3 \(\mathrm{B}_{2}\left(\mathrm{CO}_{3}\right)_{2}\)
4 \(\mathrm{B}_{2} \mathrm{H}_{6}\)
CHXI11:THE P-BLOCK ELEMENTS

316071 How many moles of \({\mathrm{\mathrm{NO}_{2}}}\) are produced when mole of B reacts with \({\mathrm{\mathrm{HNO}_{3}}}\) ?

1 5
2 4
3 3
4 8
CHXI11:THE P-BLOCK ELEMENTS

316072 Boron has an extremely high melting point because of

1 The strong van der Waal's forces between its atoms
2 The strong binding forces in the covalent polymer
3 Its ionic crystal structure
4 Allotropy
CHXI11:THE P-BLOCK ELEMENTS

316073 Consider the given statements regarding the properties of boron.
I. It is a hard refractory solid.
II. It has low melting point and high density.
III. It shows high electrical conductivity
Choose the correct statement(s).

1 Only I
2 I and III
3 Both II and III
4 All are correct
CHXI11:THE P-BLOCK ELEMENTS

316070 When boron is heated strongly with graphite, it forms

1 \({{\rm{B}}_{{\rm{12}}}}{{\rm{C}}_{\rm{3}}}{\rm{(s)}}\)
2 \(\mathrm{BC}(\mathrm{s})\)
3 \(\mathrm{B}_{2}\left(\mathrm{CO}_{3}\right)_{2}\)
4 \(\mathrm{B}_{2} \mathrm{H}_{6}\)
CHXI11:THE P-BLOCK ELEMENTS

316071 How many moles of \({\mathrm{\mathrm{NO}_{2}}}\) are produced when mole of B reacts with \({\mathrm{\mathrm{HNO}_{3}}}\) ?

1 5
2 4
3 3
4 8
CHXI11:THE P-BLOCK ELEMENTS

316072 Boron has an extremely high melting point because of

1 The strong van der Waal's forces between its atoms
2 The strong binding forces in the covalent polymer
3 Its ionic crystal structure
4 Allotropy
CHXI11:THE P-BLOCK ELEMENTS

316073 Consider the given statements regarding the properties of boron.
I. It is a hard refractory solid.
II. It has low melting point and high density.
III. It shows high electrical conductivity
Choose the correct statement(s).

1 Only I
2 I and III
3 Both II and III
4 All are correct