The stored energy in the battery does not work anymore.
HCN is a Bronsted acid; it can dissociate into H+ and CN-. And H+ is a Lewis acid because it accepts election pairs. ... In order for H+ and CN- to be formed, Hydrogen in HCN donates its electrons to Carbon. So in this sense, Hydrogen is the lewis base and Carbon is the lewis acid.
Answer: The state of maater for HgBr is solid.
Explanation:
A double displacement reaction is one in which exchange of ions take place. The salts which are soluble in water are designated by symbol (aq) and those which are insoluble in water and remain in solid form are represented by (s) after their chemical formulas.
A double displacement reaction in which one of the product is formed as a solid is called as precipitation reaction.
The balanced chemical equation is:

I think the correct answer is option A. Pure substances can be considered as compounds. Compounds are molecules made of atoms from different elements held together by chemical bonds. Pure substances are these compounds that exist alone no other substance.