316468
Assertion : The first member of a group of elements compared to that of the subsequent members in the same group shows different chemical behaviour. Reason : The first member of a group has small size, high electronegativity and no \({\text{d}}\)-orbital.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Besides its small size and high electronegativity, the first member of each group has only four valence orbitals \({\text{( 2s and 2p )}}\) available for bonding, meaning there is no expansion of the valence shell to accommodate more than four pairs of electrons, So, option (1) is correct.
CHXI11:THE P-BLOCK ELEMENTS
316469
Assertion : \(\mathrm{Al}\) forms \(\left[\mathrm{AlF}_{6}\right]^{3-}\) but \(\mathrm{B}\) does not form \(\left[\mathrm{BF}_{6}\right]^{3-}\). Reason : B does not react with fluorine.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Boron does not expand its octet due to non availability of vacant d-orbitals (sub-shell) in its valence shell, but alluminium can . Boron reacts with \(\mathrm{F}_{2}\) to form boron trifluorides. So, option (3) is correct.
CHXI11:THE P-BLOCK ELEMENTS
316470
Boron cannot form which one of the following anions?
1 \(\mathrm{BF}_{6}^{3-}\)
2 \(\mathrm{BH}_{4}^{-}\)
3 \(\mathrm{B}(\mathrm{OH})_{4}^{-}\)
4 \(\mathrm{BO}_{2}^{-}\)
Explanation:
Due to absence of d-orbitals, B cannot extend its co-valency beyond 4 and hence it forms only \(\mathrm{BF}_{4}^{-}\)and not \(\mathrm{BF}_{6}^{3-}\).
CHXI11:THE P-BLOCK ELEMENTS
316471
Statement A : Boron always forms covalent bond. Statement B : The small size of \(\mathrm{B}^{3+}\) favours formation of covalent bond.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both statements are correct.
4 Both Statements are incorrect.
Explanation:
Boron always forms covalent bond because of its small size. \(\mathrm{B}\) never forms \(\mathrm{B}^{3+}\) ion.
316468
Assertion : The first member of a group of elements compared to that of the subsequent members in the same group shows different chemical behaviour. Reason : The first member of a group has small size, high electronegativity and no \({\text{d}}\)-orbital.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Besides its small size and high electronegativity, the first member of each group has only four valence orbitals \({\text{( 2s and 2p )}}\) available for bonding, meaning there is no expansion of the valence shell to accommodate more than four pairs of electrons, So, option (1) is correct.
CHXI11:THE P-BLOCK ELEMENTS
316469
Assertion : \(\mathrm{Al}\) forms \(\left[\mathrm{AlF}_{6}\right]^{3-}\) but \(\mathrm{B}\) does not form \(\left[\mathrm{BF}_{6}\right]^{3-}\). Reason : B does not react with fluorine.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Boron does not expand its octet due to non availability of vacant d-orbitals (sub-shell) in its valence shell, but alluminium can . Boron reacts with \(\mathrm{F}_{2}\) to form boron trifluorides. So, option (3) is correct.
CHXI11:THE P-BLOCK ELEMENTS
316470
Boron cannot form which one of the following anions?
1 \(\mathrm{BF}_{6}^{3-}\)
2 \(\mathrm{BH}_{4}^{-}\)
3 \(\mathrm{B}(\mathrm{OH})_{4}^{-}\)
4 \(\mathrm{BO}_{2}^{-}\)
Explanation:
Due to absence of d-orbitals, B cannot extend its co-valency beyond 4 and hence it forms only \(\mathrm{BF}_{4}^{-}\)and not \(\mathrm{BF}_{6}^{3-}\).
CHXI11:THE P-BLOCK ELEMENTS
316471
Statement A : Boron always forms covalent bond. Statement B : The small size of \(\mathrm{B}^{3+}\) favours formation of covalent bond.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both statements are correct.
4 Both Statements are incorrect.
Explanation:
Boron always forms covalent bond because of its small size. \(\mathrm{B}\) never forms \(\mathrm{B}^{3+}\) ion.
NEET Test Series from KOTA - 10 Papers In MS WORD
WhatsApp Here
CHXI11:THE P-BLOCK ELEMENTS
316468
Assertion : The first member of a group of elements compared to that of the subsequent members in the same group shows different chemical behaviour. Reason : The first member of a group has small size, high electronegativity and no \({\text{d}}\)-orbital.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Besides its small size and high electronegativity, the first member of each group has only four valence orbitals \({\text{( 2s and 2p )}}\) available for bonding, meaning there is no expansion of the valence shell to accommodate more than four pairs of electrons, So, option (1) is correct.
CHXI11:THE P-BLOCK ELEMENTS
316469
Assertion : \(\mathrm{Al}\) forms \(\left[\mathrm{AlF}_{6}\right]^{3-}\) but \(\mathrm{B}\) does not form \(\left[\mathrm{BF}_{6}\right]^{3-}\). Reason : B does not react with fluorine.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Boron does not expand its octet due to non availability of vacant d-orbitals (sub-shell) in its valence shell, but alluminium can . Boron reacts with \(\mathrm{F}_{2}\) to form boron trifluorides. So, option (3) is correct.
CHXI11:THE P-BLOCK ELEMENTS
316470
Boron cannot form which one of the following anions?
1 \(\mathrm{BF}_{6}^{3-}\)
2 \(\mathrm{BH}_{4}^{-}\)
3 \(\mathrm{B}(\mathrm{OH})_{4}^{-}\)
4 \(\mathrm{BO}_{2}^{-}\)
Explanation:
Due to absence of d-orbitals, B cannot extend its co-valency beyond 4 and hence it forms only \(\mathrm{BF}_{4}^{-}\)and not \(\mathrm{BF}_{6}^{3-}\).
CHXI11:THE P-BLOCK ELEMENTS
316471
Statement A : Boron always forms covalent bond. Statement B : The small size of \(\mathrm{B}^{3+}\) favours formation of covalent bond.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both statements are correct.
4 Both Statements are incorrect.
Explanation:
Boron always forms covalent bond because of its small size. \(\mathrm{B}\) never forms \(\mathrm{B}^{3+}\) ion.
316468
Assertion : The first member of a group of elements compared to that of the subsequent members in the same group shows different chemical behaviour. Reason : The first member of a group has small size, high electronegativity and no \({\text{d}}\)-orbital.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Besides its small size and high electronegativity, the first member of each group has only four valence orbitals \({\text{( 2s and 2p )}}\) available for bonding, meaning there is no expansion of the valence shell to accommodate more than four pairs of electrons, So, option (1) is correct.
CHXI11:THE P-BLOCK ELEMENTS
316469
Assertion : \(\mathrm{Al}\) forms \(\left[\mathrm{AlF}_{6}\right]^{3-}\) but \(\mathrm{B}\) does not form \(\left[\mathrm{BF}_{6}\right]^{3-}\). Reason : B does not react with fluorine.
1 Both Assertion and Reason are correct and Reason is the correct explanation of the Assertion.
2 Both Assertion and Reason are correct but Reason is not the correct explanation of the Assertion.
3 Assertion is correct but Reason is incorrect.
4 Assertion is incorrect but Reason is correct.
Explanation:
Boron does not expand its octet due to non availability of vacant d-orbitals (sub-shell) in its valence shell, but alluminium can . Boron reacts with \(\mathrm{F}_{2}\) to form boron trifluorides. So, option (3) is correct.
CHXI11:THE P-BLOCK ELEMENTS
316470
Boron cannot form which one of the following anions?
1 \(\mathrm{BF}_{6}^{3-}\)
2 \(\mathrm{BH}_{4}^{-}\)
3 \(\mathrm{B}(\mathrm{OH})_{4}^{-}\)
4 \(\mathrm{BO}_{2}^{-}\)
Explanation:
Due to absence of d-orbitals, B cannot extend its co-valency beyond 4 and hence it forms only \(\mathrm{BF}_{4}^{-}\)and not \(\mathrm{BF}_{6}^{3-}\).
CHXI11:THE P-BLOCK ELEMENTS
316471
Statement A : Boron always forms covalent bond. Statement B : The small size of \(\mathrm{B}^{3+}\) favours formation of covalent bond.
1 Statement A is correct but Statement B is incorrect.
2 Statement A is incorrect but Statement B is correct.
3 Both statements are correct.
4 Both Statements are incorrect.
Explanation:
Boron always forms covalent bond because of its small size. \(\mathrm{B}\) never forms \(\mathrm{B}^{3+}\) ion.