[Sam1988]

I  just have one question. Hypothetically,  if we had an Mg and Zn simple cell  (one beaker) in a dilute acid, would the electrons on Mg go to Zinc or would the Mg react and reduce the H+ ions in the acid instead. I am presuming Mg would directly reduce H+ because Zinc is more reactive than Hydrogen. Also there is a bigger difference in reactivity between H+ and Mg too. ?

Thanks

[Aldebaran]

Generally speaking both magnesium and zinc react quite readily directly with acids. You might like to think about your question if they were immersed in some other solutions, sodium chloride (seawater) for example and perhaps if it was iron instead of zinc. There are practical applications.

[Borek]

if we had an Mg and Zn simple cell  (one beaker) in a dilute acid

That's not a cell, cell requires them to be separated and connected.

[Aldebaran]

Sam in addition to looking up sacrificial metals you might also look up lemon battery. Wikipedia has an article on it.

[Sam1988]

Generally speaking both magnesium and zinc react quite readily directly with acids. You might like to think about your question if they were immersed in some other solutions, sodium chloride (seawater) for example and perhaps if it was iron instead of zinc. There are practical applications.

Thank you for your replies, I know it is not a traditional galvanic cell. I was thinking about why electrons transfer to the less reactive metal and not directly discharging  the H+ ions in the solution at the anode.

So if I alter my question slightly ….. if we had a Zn and Fe simple cell  (one beaker) in a salt solution NaCl, would the electrons on zn go to Fe or would the zn  react and reduce the H+ ions in the electrolyte  instead. I am presuming zn  would directly reduce H+ because Fe is more reactive than Hydrogen. Also there is a bigger difference in reactivity between H+ and zn  too. ?

[Aldebaran]

So, the rules of the forum require you to do a bit of work I can’t just give you a direct answer. If you read the Wikipedia article on lemon battery all the way through you should find it enables you to answer your question. It is quite  accessible but if you still don’t get it come back.
You will find the article makes some reference to the Nernst equation but you don’t need to bother with that if you are not familiar with it.

[Borek]

What would happen to solutions containing each of the metals separately? Do you change anything just by mixing them?