Question

sodium metal reacts with water to form aqueous sodium hydroxide and hydrogen gas. which equation below best describes the balanced equation for this react 2na + 2h₂o → 2naoh (aq) + h₂ (g) na + h₂o → naoh (aq) + h₂ (g) 2na + h₂o → na₂oh (aq) + h (g) na + h₂o → naoh (aq) + h (g) s + h₂o → soh (aq) + h (g)

Explanation:

Step1: Analyze Reactants and Products

Reactants: Sodium (Na) and Water ($\ce{H2O}$). Products: Sodium Hydroxide ($\ce{NaOH(aq)}$) and Hydrogen Gas ($\ce{H2(g)}$).

Step2: Check Element Balancing

• **First Option ($\boldsymbol{2\ce{Na} + 2\ce{H2O}

ightarrow 2\ce{NaOH(aq)} + \ce{H2(g)}}$):**

• Na: Left = 2, Right = 2 (balanced).
• H: Left = $2\times2 = 4$, Right = $2\times1 + 2 = 4$ (balanced).
• O: Left = $2\times1 = 2$, Right = $2\times1 = 2$ (balanced).
• **Second Option ($\boldsymbol{\ce{Na} + \ce{H2O}

ightarrow \ce{NaOH(aq)} + \ce{H2(g)}}$):**

• Na: 1 vs 1 (ok), but H: Left = 2, Right = $1 + 2 = 3$ (unbalanced).
• Third Option: Incorrect formula ($\ce{Na2OH}$ is wrong, should be $\ce{NaOH}$ or $\ce{Na2O}$ etc.), and H is as single atom (invalid, $\ce{H2}$ is correct form).
• Fourth Option: H is single atom (invalid, $\ce{H2}$ is correct), and balancing fails.
• Fifth Option: Reactant is Sulfur (S) not Sodium (Na), so invalid.

Answer:

A. $2\ce{Na} + 2\ce{H2O}
ightarrow 2\ce{NaOH(aq)} + \ce{H2(g)}$