Question

Which species contains only covalent bonds?

a) `AlF_3`
b) `NH_4NO_3`
c) `H_2SO_4`
d) `K_2Cr_2O_7`

I know that the answer is c), but could someone please explain why? Thank you so much!

Answer 1

You got three ionic solids.....

Explanation:

...and only the one distillable liquid. Aluminum fluoride, ammonium nitrate, and potassium dichromate are made of discrete ions...and the parent ions are easy to assess from the formulae: `Al^(3+)`; `Al^(3+), 3xxF^-`; `NH_4^(+), NO_3^(-)`; `2xxK^+, Cr_2O_7^(2-)`.

On the other hand, sulfuric acid...is the hydrate of a non-metal oxide, an oxyacid; and this is molecular, and thus `d` is the best answer. Depending where you are you just have to recognize the type of material you got.