Reaction of Metals with Water

Question 1 What happens when potassium react with water?

Question 2 What happens when sodium react with water?

Question 3 What happens when aluminium react with water?

Question 4 What happens when zinc react with water?

Reaction of Metals with Water

Metals react with water to form hydroxide, hydrogen gas and heat is evolved.

2K +2H₂O ———-> 2KOH + H_{2 +heat                   
       cold}

_{2Na +} 2H₂O ———-> 2NaOH + H_{2 +heat
          cold} 

2Na (s) + 2 H₂0 (l) —-> 2 NaOH (aq) + H₂ (g) +heat

Ca(s) + 2 H₂0 (l) —–> Ca(OH)₂  (aq) +  H₂ (g)

Mg(s) + 2 H₂0 (l) —–> Mg(OH)₂  (aq) + H₂ (g)

2Al (s) + 3 H₂0 (l) —–> Al₂O₃  (s) + 3 H₂ (g)

Zn (s) + H₂0 (l) —–> ZnO(s) + H₂ (g)

3 Fe (s) + 4 H₂0 (l) —–> Fe₃O₄  (s) + 4 H₂ (g)

Zn, Al, Fe react with water to form metal oxide.

The reaction of Ca with water is less violent. The heat evolved in not sufficient for hydrogen to catch fire.

Ca starts floating because bubbles of hydrogen gas formed stick to the surface of metal.