Question

Of the following, the element that reacts most readily with hydrochloric acid to produce hydrogen gas is:

• A. $Cu$
• B. $Hg$
• C. $Ag$
• D. $Zn$

Answer 1

The correct option is D $Zn$

Among all the elements listed in the question, according to the electrochemical series, $Zn$ is the best reducing agent. $Zn$ lies towards the top of this series and hence has a negative reduction potential value and can easily lose electrons.

When hydrochloric acid is reduced, it produces Hydrogen gas. Thus, $Zn$ being the best reducing agent, reduces $HCl$ fastest to give Hydrogen gas.

The equation can be written as,

$Zn$ $+$ $2HCl$ $=>$ ${ZnCl}_2$ $+$ $H_2$