313673
Assertion : Lattice enthalpy of \(\mathrm{NaCl}\) is \(788 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\). Reason : \(\mathrm{NaCl}\) is a solid with 3D crystal structure.
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:
The lattice enthalpy of \(\mathrm{NaCl}\) (sodium chloride) is \(788 \mathrm{~kJ} / \mathrm{mol}\). The sodium cations and chloride anions are held together in a crystal lattice by strong electrostatic forces of attraction due to their opposite charges. So it is a solid. Both the statements are correct but reason is not the correct explanation. So the option (2) is correct.
CHXI04:CHEMICAL BONDING AND MOLECULAR STRUCTURE
313674
Which of the following substance has the highest melting point?
1 \(\mathrm{BaO}\)
2 \(\mathrm{MgO}\)
3 \(\mathrm{KCl}\)
4 \(\mathrm{NaCl}\)
Explanation:
Melting point depends upon lattice energy. \(\mathrm{NaCl}\) and \(\mathrm{KCl}\) have unit charge on their ions while \(\mathrm{MgO}\) and \(\mathrm{BaO}\) have two units of charge, therefore lattice energies of \(\mathrm{MgO}\) and \(\mathrm{BaO}\) are expected to be larger than those of \(\mathrm{NaCl}\) and \(\mathrm{KCl}\) Since, \(\mathrm{Mg}^{2+}\) is smaller than \(\mathrm{Ba}^{2+}\), therefore, \(\mathrm{MgO}\) has the higher lattice energy and hence \(\mathrm{MgO}\) has the highest melting point.
CHXI04:CHEMICAL BONDING AND MOLECULAR STRUCTURE
313675
Lattice energy depends on
1 Only radius of cation
2 Only radius of anion
3 Cation to anion radius ratio
4 Sum of the radii of cation and anion
Explanation:
Lattice energy is directly proportional to charge and inversely proportional to the size of the ion.
313673
Assertion : Lattice enthalpy of \(\mathrm{NaCl}\) is \(788 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\). Reason : \(\mathrm{NaCl}\) is a solid with 3D crystal structure.
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:
The lattice enthalpy of \(\mathrm{NaCl}\) (sodium chloride) is \(788 \mathrm{~kJ} / \mathrm{mol}\). The sodium cations and chloride anions are held together in a crystal lattice by strong electrostatic forces of attraction due to their opposite charges. So it is a solid. Both the statements are correct but reason is not the correct explanation. So the option (2) is correct.
CHXI04:CHEMICAL BONDING AND MOLECULAR STRUCTURE
313674
Which of the following substance has the highest melting point?
1 \(\mathrm{BaO}\)
2 \(\mathrm{MgO}\)
3 \(\mathrm{KCl}\)
4 \(\mathrm{NaCl}\)
Explanation:
Melting point depends upon lattice energy. \(\mathrm{NaCl}\) and \(\mathrm{KCl}\) have unit charge on their ions while \(\mathrm{MgO}\) and \(\mathrm{BaO}\) have two units of charge, therefore lattice energies of \(\mathrm{MgO}\) and \(\mathrm{BaO}\) are expected to be larger than those of \(\mathrm{NaCl}\) and \(\mathrm{KCl}\) Since, \(\mathrm{Mg}^{2+}\) is smaller than \(\mathrm{Ba}^{2+}\), therefore, \(\mathrm{MgO}\) has the higher lattice energy and hence \(\mathrm{MgO}\) has the highest melting point.
CHXI04:CHEMICAL BONDING AND MOLECULAR STRUCTURE
313675
Lattice energy depends on
1 Only radius of cation
2 Only radius of anion
3 Cation to anion radius ratio
4 Sum of the radii of cation and anion
Explanation:
Lattice energy is directly proportional to charge and inversely proportional to the size of the ion.
313673
Assertion : Lattice enthalpy of \(\mathrm{NaCl}\) is \(788 \mathrm{~kJ}\) \(\mathrm{mol}^{-1}\). Reason : \(\mathrm{NaCl}\) is a solid with 3D crystal structure.
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:
The lattice enthalpy of \(\mathrm{NaCl}\) (sodium chloride) is \(788 \mathrm{~kJ} / \mathrm{mol}\). The sodium cations and chloride anions are held together in a crystal lattice by strong electrostatic forces of attraction due to their opposite charges. So it is a solid. Both the statements are correct but reason is not the correct explanation. So the option (2) is correct.
CHXI04:CHEMICAL BONDING AND MOLECULAR STRUCTURE
313674
Which of the following substance has the highest melting point?
1 \(\mathrm{BaO}\)
2 \(\mathrm{MgO}\)
3 \(\mathrm{KCl}\)
4 \(\mathrm{NaCl}\)
Explanation:
Melting point depends upon lattice energy. \(\mathrm{NaCl}\) and \(\mathrm{KCl}\) have unit charge on their ions while \(\mathrm{MgO}\) and \(\mathrm{BaO}\) have two units of charge, therefore lattice energies of \(\mathrm{MgO}\) and \(\mathrm{BaO}\) are expected to be larger than those of \(\mathrm{NaCl}\) and \(\mathrm{KCl}\) Since, \(\mathrm{Mg}^{2+}\) is smaller than \(\mathrm{Ba}^{2+}\), therefore, \(\mathrm{MgO}\) has the higher lattice energy and hence \(\mathrm{MgO}\) has the highest melting point.
CHXI04:CHEMICAL BONDING AND MOLECULAR STRUCTURE
313675
Lattice energy depends on
1 Only radius of cation
2 Only radius of anion
3 Cation to anion radius ratio
4 Sum of the radii of cation and anion
Explanation:
Lattice energy is directly proportional to charge and inversely proportional to the size of the ion.
