Question

A 0.50 g sample of Mg(s) was placed in a solution of HCl(aq), where it reacted completely. Which of the

following equations best represents their reaction?
a.) Mg(s)+2HCl--->MgCl2+2H^1+
b.) Mg(s)+2H^1+--->Mg^2+ + H2(g)
c.) Mg(s)+HCl--->MgCl2+H2(g)
d.) Mg(s)+2HCl--->Mg^2+ +Cl2(g)+H2(g)

Answer 1

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!