Which compound is most likely a powerful and dangerous acid?

 Hydrofluoric acid is a powerful and dangerous acid. 

Never mix bleach and amonia. That combination is toxic to humans and animals. If the mix is subjected to open air with a oerosn in it, death is likely. so make sure to never mix that Very very bad

Answerd. may include all of these are many definitions of bases: the  brønsted-lowry definition of acids and bases says that bases are proton acceptors.the arrhenius definition of acids and bases says that bases increase [oh⁻] in solution (thereby producing oh⁻ ions)the lewis definition of acids and bases says that bases donate electron pairs.therefore, the sensible answer is that a base may include all of the described characteristics.

Reducing agents  oxidized by the reaction