Question

(1) Which is a binary molecular compound? a)CO2 (b) NaCl (c) KOH (d) Ba( NO3)2 2) Which substance is composed of molecules? (a) KOH (b) CuCL2 (c) H2O (d) Al

Answer 1

Well, for `(a), (b),` `(c)`, and `(d)`. you gots only the ONE molecular compound....and that is `CO_2(g)`

Explanation:

Sodium chloride, and potassium hydroxide, are certainly binary, containing only TWO (or THREE) types of atoms, but they are NOT molecular, and consist of infinite arrays of positively and negatively charged ions, the which are held together by electrostatic interaction.

On the other hand, `CO_2`, is composed of oxygen, and carbon atoms that are covalently bound to form discrete `CO_2` molecules. The molecular nature of `CO_2` means that this species has intrinsically LOWER melting and boiling points. `CO_2(g)` sublimes at `-78` `""^@C` under one atmosphere....

On the other hand, other hand, the melting points of the non-molecular, ionic materials, will be sky-high...

And for the second series ONLY water is molecular. The boiling point, and freezing point are rather elevated for a molecular compound, and hydrogen-bonding accounts for its relative involatility.

You should look up the melting points of EACH substance in each series, to ensure that I am not telling pork pies (and also as a scientist you must interrogate the data!)