Hydroferocyanic or Hydroferrocyanic: How To spell?
The word Hydroferocyanic is misspelled against Hydroferrocyanic, an adjective meaning "Pertaining to, or containing, or obtained from, hydrogen, ferrous iron, and cyanogen; as, hydroferrocyanic acid. See Ferrocyanic."
Hydroferrocyanic has double "rr" is mispronounced as "r"Remember double 'RR' in between the strings hydrofe & ocyanic which should not be misspelled with single 'R'
Wrong Spelling:  hydrofe-r-ocyanic  Correct Spelling:  hydrofe-rr-ocyanic 
Find more incorrect spellings of Hydroferrocyanic to spell right way.