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Why is the melting point of MgO higher than that of NaCl?
AMg is heavier than Na across all cases
BMgO has covalent bonds, NaCl is ionic
CNa and Cl react slower under typical conditions
DMgO has higher charge product on ions, increasing lattice energy
Answer & Solution
Correct answer: D. MgO has higher charge product on ions, increasing lattice energy
1. Lattice energy grows with the product of ion charges.
2. MgO has Mg^2+ and O^2-, giving a charge product of 4.
3. NaCl has +1 and -1 ions, charge product 1.
4. So MgO holds together about four times more strongly.
5. Hence MgO melts at a higher temperature than NaCl.
_Source: Selina Concise Chemistry ICSE Class 10, Ch 2 'Chemical Bonding'_
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