Question

Why does ice have a higher melting point than solid ammonia?

Answer 1

Clearly because GREATER intermolecular forces of attraction operate within ice than in solid ammonia....

Explanation:

And we really compare apples with oranges. Water and ammonia are different materials, with different characteristic properties. Both solvents exhibit intermolecular hydrogen-bonding, which is a potent intermolecular force that elevates the boiling point. For water, `"normal boiling point"` `=100` `""^@C`, whereas for ammonia `"normal boiling point"` `=-33.3` `""^@C`. Both of these boiling points are EXCEPTIONALLY high for such small molecules... I will let you hunt down the melting points...well, one you know...