Question

What happens when magnesium is left in seawater?

Answer 1

Well, have you done the experiment.....?

Explanation:

My guess would be that the magnesium metal would slowly oxidize....

`Mg(s) stackrel(H_2O)rarrMg^(2+) + 2e^(-)`

....and reduce the hydrogen in water....

`H_2O(l) + e^(-) rarr 1/2H_2(g)+HO^-`

...to give the overall reaction.....

`Mg(s) + 2H_2O(l) rarr H_2(g)uarr +Mg(OH)_2(aq)`

Certainly, when you put a strip of magnesium metal into hot tap water, the water becomes basic as vizualized by an acid-base indicator.....but anyway, you have got the experiment outlined. Take a beaker of seawater, measure its `pH`, and add a strip of magnesium ribbon. Take the `pH` of the solution periodically, and closely observe the appearance of the metal strip.....