Question

reactivity series of metals
lithium
rubidium
potassium
barium
calcium
sodium
magnesium
aluminum
manganese
zinc
chromium
iron
cobalt
nickel
tin
lead
hydrogen
copper
silver
mercury
platinum
gold
(increasing reactivity arrow)
options:
aluminum
calcium
copper
nickel

Explanation:

To solve this, we analyze the reactivity series: the higher up a metal is, the more reactive it is. Let's check each option:

• Aluminum: Positioned above Zinc, Iron, etc.
• Calcium: Positioned above Sodium, Magnesium, Aluminum (so more reactive than Aluminum).
• Copper: Positioned below Hydrogen, much less reactive than Aluminum and Calcium.
• Nickel: Positioned below Iron, Cobalt, and above Tin/Lead, but below Aluminum and Calcium.

Among the options, Calcium is highest in the reactivity series (most reactive).

Answer:

B. Calcium (assuming the options are labeled, but based on the list, Calcium is the most reactive among the given choices as it’s higher in the series than Aluminum, Copper, and Nickel).