Question

What is \( x \) in the following reaction? \[ {Al} (s) + {NaOH} (aq) + {H}_2O (l) \rightarrow x + {H}_2 (g) \]

• A. \( {Na}_2 [{Al(OH)}_4]^- \)
• B. \( {Na}^+ [{Al(OH)}_4]^- \)
• C. \( {Na}_2 [{Al(OH)}_6]^- \)
• D. \( {Na}^+ [{Al(OH)}_6]^- \)

Hint:

Aluminum reacts with \({NaOH}\) to form a soluble aluminate complex \([{Al(OH)}_4]^-\). Always check the oxidation states and solubility of the resulting compounds.

Answer 1

The Correct Option is B

Step 1: Understanding the reaction mechanism. When aluminum reacts with sodium hydroxide in the presence of water, it forms a soluble complex ion. The reaction proceeds as follows: \[ {Al} + {NaOH} + {H}_2O \rightarrow {Na}^+ [{Al(OH)}_4]^- + {H}_2 \] Step 2: Identifying the product. The aluminum hydroxide complex formed is \([{Al(OH)}_4]^-\), which is stabilized by sodium ions \({Na}^+\). This corresponds to option (B).