Question

when placed into water, which formula represents hydrochloric acid?\
\\(\ce{hclo3}\\)\
\\(\ce{hclo4}\\)\
\\(\ce{hclo2}\\)\
\\(\ce{hcl}\\)

Explanation:

Hydrochloric acid is an aqueous solution of hydrogen chloride gas. The chemical formula for hydrogen chloride (and thus hydrochloric acid when dissolved in water) is HCl. The other options: $\ce{HClO_3}$ is chloric acid, $\ce{HClO_4}$ is perchloric acid, and $\ce{HClO_2}$ is chlorous acid.

Answer:

D. HCl