“Exothermic,” Maya whispered, recording the temperature rise. The magnesium was even more reactive than zinc. It had ripped the copper from the solution with such force that it generated heat.
“Don’t be a hero yet,” Lin warned, pouring 2 cm³ of the deep, sapphire-blue copper(II) sulphate solution into each tube. The liquid was beautiful, like a piece of the ocean trapped in glass.
Maya stood up, her voice steady. “Magnesium is the most reactive, then zinc, then copper. Because a more reactive metal will displace a less reactive metal from its salt solution.” chemistry form 4 experiment 5.1
Ravi carefully dropped a few granules of zinc into the next tube. For a moment, nothing. Then, a miracle. The deep blue colour began to bleed away from the zinc, as if an invisible eraser was moving upwards. Simultaneously, a reddish-brown dust started to bloom on the surface of the zinc granules, like rust forming in fast-forward.
“Correct. And the reactivity series order from this experiment?” “Don’t be a hero yet,” Lin warned, pouring
Maya, the cautious one, read the steps aloud. “First, we label four test tubes. One is the control.”
Ravi, whose fingers were always a little too eager, held a small coil of magnesium ribbon. It looked like a piece of dull, grey tinsel. “This looks harmless,” he smirked. “Magnesium is the most reactive, then zinc, then copper
“Magnesium!” the class shouted.
He dropped the ribbon into the final bath of blue.
The experiment was simple, yet dangerous to a careless hand. Procedure 5.1: Investigate the reaction of metals with the salt solution of another metal.
Lin nodded, swirling the last of the pale, colourless solution down the sink. “That’s not war,” she smiled. “That’s displacement. And now we know how to prove who belongs where.”