---
title: "Industrial production of titanium metal begins with the high-temperature carbochlorination of titanium dioxide, represented by the balanced chemical equation below.  \\[ \\text{TiO}_2(s) + 2\\,\\text{C}(s) + 2\\,\\text{Cl}_2(g) \\rightarrow \\text{TiCl}_4(l) + 2\\,\\text{CO}(g) \\]  A thermochemist uses the following standard enthalpies of reaction at \\(298\\text{ K}\\) to determine the overall enthalpy change of this synthesis:  \\[ \\text{Reaction 1: } \\text{Ti}(s) + 2\\,\\text{Cl}_2(g) \\rightarrow \\text{TiCl}_4(l) \\quad \\Delta H^\\circ_1 \\]  \\[ \\text{Reaction 2: } \\text{Ti}(s) + \\text{O}_2(g) \\rightarrow \\text{TiO}_2(s) \\quad \\Delta H^\\circ_2 \\]  \\[ \\text{Reaction 3: } \\text{CO}(g) \\rightarrow \\text{C}(s) + \\dfrac{1}{2}\\,\\text{O}_2(g) \\quad \\Delta H^\\circ_3 \\]  Based on the reactions provided, which of the following expressions correctly represents the value of \\(\\Delta H^\\circ_{\\text{rxn}}\\) for the carbochlorination process?"
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url: "https://nerd-notes.com/ubq/121471/"
date_modified: "2026-08-23T05:04:45+00:00"
---

# Industrial production of titanium metal begins with the high-temperature carbochlorination of titanium dioxide, represented by the balanced chemical equation below.

\[ \text{TiO}_2(s) + 2\,\text{C}(s) + 2\,\text{Cl}_2(g) \rightarrow \text{TiCl}_4(l) + 2\,\text{CO}(g) \]

A thermochemist uses the following standard enthalpies of reaction at \(298\text{ K}\) to determine the overall enthalpy change of this synthesis:

\[ \text{Reaction 1: } \text{Ti}(s) + 2\,\text{Cl}_2(g) \rightarrow \text{TiCl}_4(l) \quad \Delta H^\circ_1 \]

\[ \text{Reaction 2: } \text{Ti}(s) + \text{O}_2(g) \rightarrow \text{TiO}_2(s) \quad \Delta H^\circ_2 \]

\[ \text{Reaction 3: } \text{CO}(g) \rightarrow \text{C}(s) + \dfrac{1}{2}\,\text{O}_2(g) \quad \Delta H^\circ_3 \]

Based on the reactions provided, which of the following expressions correctly represents the value of \(\Delta H^\circ_{\text{rxn}}\) for the carbochlorination process?

Industrial production of titanium metal begins with the high-temperature carbochlorination of titanium dioxide, represented by the balanced chemical equation below.

\[ \text{TiO}_2(s) + 2\,\text{C}(s) + 2\,\text{Cl}_2(g) \rightarrow \text{TiCl}_4(l) + 2\,\text{CO}(g) \]

A thermochemist uses the following standard enthalpies of reaction at \(298\text{ K}\) to determine the overall enthalpy change of this synthesis:

\[ \text{Reaction 1: } \text{Ti}(s) + 2\,\text{Cl}_2(g) \rightarrow \text{TiCl}_4(l) \quad \Delta H^\circ_1 \]

\[ \text{Reaction 2: } \text{Ti}(s) + \text{O}_2(g) \rightarrow \text{TiO}_2(s) \quad \Delta H^\circ_2 \]

\[ \text{Reaction 3: } \text{CO}(g) \rightarrow \text{C}(s) + \dfrac{1}{2}\,\text{O}_2(g) \quad \Delta H^\circ_3 \]

Based on the reactions provided, which of the following expressions correctly represents the value of \(\Delta H^\circ_{\text{rxn}}\) for the carbochlorination process?

- **A.** \(\Delta H^\circ_{\text{rxn}} = \Delta H^\circ_1 - \Delta H^\circ_2 + 2\,\Delta H^\circ_3\)
- **B.** \(\Delta H^\circ_{\text{rxn}} = \Delta H^\circ_1 - \Delta H^\circ_2 - 2\,\Delta H^\circ_3\)
- **C.** \(\Delta H^\circ_{\text{rxn}} = \Delta H^\circ_1 - \Delta H^\circ_2 - \Delta H^\circ_3\)
- **D.** \(\Delta H^\circ_{\text{rxn}} = -\Delta H^\circ_1 + \Delta H^\circ_2 - 2\,\Delta H^\circ_3\)

*The answer key and step-by-step explanation are available to logged-in users at https://nerd-notes.com/ubq/121471/*