This type of reaction is called __________.
Fe-C Reaction Identification
The question describes an invariant reaction in the Fe-C system: Liquid + $\delta \rightleftharpoons \gamma$ at 1493 °C. We need to identify the type of this reaction.
Invariant Reaction Types
Invariant reactions occur at a specific temperature and composition where multiple phases coexist in equilibrium. The common types are:
- Eutectic: One liquid phase transforms into two solid phases. (Liquid $\rightleftharpoons$ Solid 1 + Solid 2)
- Eutectoid: One solid phase transforms into two different solid phases. (Solid 1 $\rightleftharpoons$ Solid 2 + Solid 3)
- Peritectic: One liquid phase reacts with one solid phase to form a different solid phase. (Liquid + Solid 1 $\rightleftharpoons$ Solid 2)
- Monotectic: One liquid phase transforms into another liquid phase and one solid phase. (Liquid 1 $\rightleftharpoons$ Liquid 2 + Solid)
Analyzing the Fe-C Reaction
The given reaction is: Liquid + $\delta \rightleftharpoons \gamma$
In this reaction:
- We start with a Liquid phase and a solid $\delta$ phase.
- These react to form a single, different solid $\gamma$ phase.
This matches the definition of a peritectic reaction, where a liquid and a solid combine to form a new solid phase.
Conclusion
Therefore, the invariant reaction Liquid + $\delta \rightleftharpoons \gamma$ in the Fe-C system is classified as a peritectic reaction.
Important Questions from Phase Diagrams Gibbs Phase Rule Variance
Maximum number of phases that can be in equilibrium for a 5-component system at constant temperature and pressure is ________ (in integer).
- Match the names listed in Group I with the reactions listed in Group II
Group I Group II P. Eutectic 1. $\gamma + \beta \rightarrow \alpha$ Q. Peritectic 2. $L \rightarrow \alpha + \beta$ R. Peritectoid 3. $L_1 \rightarrow L_2 + \alpha$ S. Monotectic 4. $L + \beta \rightarrow \alpha$ Identify the type of the following invariant reaction:
$liquid \ 1 + solid \ 1 \rightleftharpoons solid \ 2$
- Two phases $\alpha$ and $\beta$ are in thermodynamic equilibrium. If x and y are the only components present in the phases $\alpha$ and $\beta$ and if $\mu_i^j$ represents the chemical potential of component i in phase j, then the condition for equilibrium is
Consider the phase diagram of a one component system given below. $V_\alpha$, $V_\beta$, and $V_{Liquid}$ are the molar volumes of $\alpha$, $\beta$, and liquid phases, respectively.
Which one of the following statements is TRUE?
Given: The change in molar enthalpies, $\Delta H^{\alpha \to \beta}$ and $\Delta H^{\beta \to Liquid}$, are positive.
