When a metal and sulphuric acid react with each other, metal displaces hydrogen, which is higher in the reactivity series. Identify the metal for which the bubbling of hydrogen gas will be the fastest.

The bubbling of hydrogen gas will be the fastest for magnesium. In the reactivity series, the higher a metal is, the more readily it reacts with acids to displace hydrogen gas. Magnesium is the most reactive metal, followed by aluminium, zinc, and iron. The faster the reaction, the greater the bubbling of hydrogen gas.