Which of the following metals will not react with dilute hydrochloric acid? Justify answer.
Zinc, Gold, Copper, Magnesium
[2 Marks]

Only metals which lie above hydrogen in the reactivity series react with dilute acids to release ${\text{H}}_2$.
[1 Mark]


As gold ($Au$) and copper ($Cu$) lies below hydrogen in the reactivity series both will not react with dilute acids.
Therefore, gold and copper will not react with dilute hydrochloric acid while zinc and magnesium will react that will result in the formation of respective metal salts along with the evolution of hydrogen gas. [1 Mark]