Question

question 42 (1 point) listen magnesium hydroxide solid decomposes to give solid magnesium oxide and liquid water. the balanced chemical equation for the reaction is: 1) mgo₂(s) → mgo(s) + h₂o(l) 2) 2mn(oh)₂(s) → mno(s) + h₂o(l) 3) mg(oh)₂(s)→ mgo(s) + h₂o(l) 4) mno (s) → mno₂(s) + h₂o(l)

Explanation:

Step1: Identify Reactant

The reactant should be magnesium hydroxide, formula \( \text{Mg(OH)}_2 \). Check each option:

• Option 1: Reactant is \( \text{MgO}_2 \) (incorrect, not magnesium hydroxide).
• Option 2: Reactant is \( \text{Mn(OH)}_2 \) (manganese hydroxide, not magnesium).
• Option 3: Reactant is \( \text{Mg(OH)}_2 \) (correct reactant).
• Option 4: Reactant is \( \text{MnO} \) (incorrect, not magnesium hydroxide).

Step2: Check Balanced Equation

For \( \text{Mg(OH)}_2(s)
ightarrow \text{MgO}(s) + \text{H}_2\text{O}(l) \):

• Mg: 1 on left, 1 on right.
• O: 2 (from \( \text{OH}^- \times 2 \)) on left; 1 (MgO) + 1 (H₂O) = 2 on right.
• H: 2 (from \( \text{OH}^- \times 2 \)) on left; 2 (H₂O) on right. Equation is balanced.

Answer:

1. \( \text{Mg(OH)}_2(s)

ightarrow \text{MgO}(s) + \text{H}_2\text{O}(l) \)