Question

consider the redox reaction below. 2al(s) + 6hcl(aq)→2alcl3(aq)+3h2(g) which statement correctly describes a half - reaction that is taking place? hydrogen is oxidized from +1 to 0. chlorine is reduced from -1 to 0. aluminum is oxidized from 0 to +3. hydrogen is reduced from 0 to -1.

Explanation:

1. Oxidation is the loss of electrons and increase in oxidation state. Reduction is the gain of electrons and decrease in oxidation state.
2. In the reactant Al(s), the oxidation state of aluminum is 0. In the product \(AlCl_3(aq)\), the oxidation state of aluminum is +3 as chlorine has an oxidation - state of - 1 and in \(AlCl_3\), \(x+3\times(-1)=0\) (where \(x\) is the oxidation state of Al), so \(x = + 3\). Aluminum loses 3 electrons and is oxidized.
3. In \(HCl\), the oxidation state of hydrogen is +1 and in \(H_2\), the oxidation state of hydrogen is 0. Hydrogen is reduced. Chlorine has an oxidation state of - 1 in \(HCl\) and - 1 in \(AlCl_3\), so chlorine is neither oxidized nor reduced.

Answer:

Aluminum is oxidized from 0 to +3.