Look at the activity series and select which two of the following reactions would happen on their own. (Remember, if the lone element is more active than the metal in the compound, the lone element will react and replace the metal in the compound.) Lithium (Li) Potassium (K)
Calcium (Ca)
Sodium (Na)
Aluminum (Al)
Zinc (Zn)
Iron (Fe)
Tin (Sn)
Lead (Pb)
(Hydrogen) (H)
Copper (Cu)
Silver (Ag)
Gold (Au)

A.
2Li + ZnBr2 ->2LiBr + Zn
B.
Al + 3LiCl ->AlCl3 + 3Li

C.
Sn + ZnSe ->SnSe + Zn

D.
3Ca + Al2O3 ->2Al + 3CaO

2Li + ZnBr2 ->2LiBr + Zn

3Ca + Al2O3 ->2Al + 3CaO

Explanation:

Spontaneous reactions are reactions that can happen on their own. For a spontaneous reaction to occur, a metal that is higher in the activity series must displace a metal that is lower in the activity series from its solution and not vice versa.

If we look at the two reactions selected in the answer, lithium is above zinc in the activity series and calcium is above aluminum in the activity series hence the two reactions occur spontaneously.

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