Question

what are the coefficients for the following chemical reaction when it is properly balanced?

hcl + mg → mgcl2 + h2

a. 2,1,1,1
b. 2,1,2,2
c. 1,2, 1/2,1
d. 1,1,1,2
e. 3,1,2,2

clear my choice

Explanation:

Step1: Analyze Cl atoms

On the product side, \( \text{MgCl}_2 \) has 2 Cl atoms. So, \( \text{HCl} \) (which has 1 Cl per molecule) needs a coefficient of 2 to balance Cl: \( 2\text{HCl} + \text{Mg} \to \text{MgCl}_2 + \text{H}_2 \)

Step2: Analyze H atoms

Left side: \( 2\text{HCl} \) has 2 H. Right side: \( \text{H}_2 \) has 2 H (balanced now).

Step3: Analyze Mg atoms

Left side: 1 Mg. Right side: \( \text{MgCl}_2 \) has 1 Mg (balanced).
So coefficients are 2 (HCl), 1 (Mg), 1 (MgCl₂), 1 (H₂).

Answer:

a. 2, 1, 1, 1