Question

which chemical equation represents a redox reaction? (1 point)
○ ticl₄(s)+2h₂o(g)→tio₂(s)+4hcl(g)
○ cao(s)+sio₂(s)→casio₃(l)
○ fe₂o₃(s)+2al(s)→al₂o₃(s)+2fe(l)

Explanation:

Step1: Determine oxidation states

In \(TiCl_{4}(s)+2H_{2}O(g)\to TiO_{2}(s)+4HCl(g)\), for \(Ti\): in \(TiCl_{4}\), \(Ti\) is \(+ 4\), in \(TiO_{2}\), \(Ti\) is \(+4\). For \(H\): in \(H_{2}O\), \(H\) is \(+1\), in \(HCl\), \(H\) is \(+1\). For \(O\): in \(H_{2}O\) and \(TiO_{2}\), \(O\) is \(-2\). For \(Cl\): in \(TiCl_{4}\) and \(HCl\), \(Cl\) is \(-1\). No change in oxidation states.

Step2: Check another equation

In \(CaO(s)+SiO_{2}(s)\to CaSiO_{3}(l)\), for \(Ca\): in \(CaO\), \(Ca\) is \(+2\), in \(CaSiO_{3}\), \(Ca\) is \(+2\). For \(Si\): in \(SiO_{2}\), \(Si\) is \(+4\), in \(CaSiO_{3}\), \(Si\) is \(+4\). For \(O\): in \(CaO\), \(SiO_{2}\) and \(CaSiO_{3}\), \(O\) is \(-2\). No change in oxidation states.

Step3: Analyze the third equation

In \(Fe_{2}O_{3}(s)+2Al(s)\to Al_{2}O_{3}(s)+2Fe(l)\), for \(Fe\): in \(Fe_{2}O_{3}\), \(Fe\) is \(+3\), in \(Fe\), \(Fe\) is \(0\) (reduction). For \(Al\): in \(Al\), \(Al\) is \(0\), in \(Al_{2}O_{3}\), \(Al\) is \(+3\) (oxidation). There are changes in oxidation states.

Answer:

\(Fe_{2}O_{3}(s)+2Al(s)\to Al_{2}O_{3}(s)+2Fe(l)\)