Question

Name the ions furnished by: ​
an acid​

Answer 1

The ions produced by acids in solution are hydrogen $\left(H^{+}\right)$ions.
For example,
$HCl\left(l\right)\to H^{+}\left(aq\right)+{Cl}^{-}\left(aq\right)$
Hydrochloric acid produces $H^{+}$ions when it is added to water.