Answer:
B) Mg(s) + 2H+(aq) --> Mg2+ + H2(g)
Step-by-step explanation:
First, write the equation. This is a single replacement reaction. Make sure to label which parts will ionize:
Mg(s) + HCl(aq) --> H2(g) + MgCl2(aq)
- Chlorides ionize
Next, balance the equation:
Mg(s) + 2HCl(aq) --> H2(g) + MgCl2(aq)
Then, separate the parts that will ionize (the ones labeled aq) and cancel them out if they're the same on both sides:
Mg(s) + 2H+(aq) --> Mg2+(aq) + H2(g)
- chlorine got canceled out because it was aqueous on both sides of the reaction
This is your final answer!