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!

1 Answer
Jan 7, 2018

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.