The correct option is Below lead and above copper.
Explanation
The reactivity series (or activity series) is a list of metals arranged in the order of their decreasing chemical reactivity. Although hydrogen is a non-metal, it is included in this series as a reference point because, like metals, it can lose electrons to form positive ions ($H^+$). Its position determines which metals can displace hydrogen from dilute acids and water.
Analysis of Position
The standard order of common elements in the reactivity series is as follows:
- Potassium (K) - Most Reactive
- Sodium (Na)
- Calcium (Ca)
- Magnesium (Mg)
- Aluminium (Al)
- Zinc (Zn)
- Iron (Fe)
- Lead (Pb)
- Hydrogen (H)
- Copper (Cu)
- Mercury (Hg)
- Silver (Ag)
- Gold (Au) - Least Reactive
Hydrogen is positioned below Lead (Pb) and above Copper (Cu). This placement signifies that metals like Lead, Iron, and Zinc are more reactive than hydrogen and can displace it from dilute acids, whereas metals like Copper, Silver, and Gold are less reactive than hydrogen and cannot displace it.
Key Takeaway: Hydrogen acts as the dividing line in the activity series; it is placed between Lead and Copper. Metals placed above hydrogen can displace it from dilute acids, while those placed below it cannot.