Which of the following statement is not correct?

Options

A. The reaction `Or_(2)O_(3) +2Al rarr Al_(2)O_(3) + 2Cr` is thermodynamically feasible as is apparent from the Gibbs energy value but it does not take place at room temperature.
B. Under certains conditions, `Mg` can reduce `SiO_(2)` and `Si` can rection `MgO`.
C. Out of `C and CO,C ` is a better reduction agent than `CO` below `673K` but `CO` is a more effective reducing agent than `C` above `673K`.
D. Out of `C and Co,C` is a better readucing equal than `CO` the reduction of `ZnO` is `Zn`

Answer

c

Explanation

When carbon reacts with dioxygen ,two reaction are possible
`C(s) +O_(2)(g) rarr CO_(2)(g)`
`2C(s) + O_(2)(g) rarr 2CO(g)`
The carbon monoxide thus produced can be also reach with oxygen to form carbon dioxide
`2CO(g) + O_(2)(g) rarr 2CO_(2)(g)`
The three (cross) one smother at `673 K` .Below this tempetare of `CO_(2)` from `C` as well as from `CO` is energetically more faverable and above this temperature other .But since `CO` can be more realy oxidered to `CO_(2)` than `C` as `CO_(2)` is a reson effective reduction agent than `C` below `673K`
However where `673 K` ,`CO ` is move stable and bence .Therefore , above `673 K` C ias better rethuring agent then `CO`
(1) Reactions which are thermodynamically fessible also requird certain amount of silivation energy barrier.
(2) Acording to Ellinghum diagram below `1966k, Delta_(f)G^(Ө)` "curve for" `Si-SiO_(2)`, lies above the `Delta_(f)G^(Ө)` curve ofr `Mg-MgO`.Therefore, at temperatures below `1966K`, `Mg` can reduce `SiO_(2)` to silicon :
`SiO_(2)+2Mgoverset(gt1966 K)to 2MgO+Si`
(3) However above `1966 K` the `DEelta_(T)G` curve for so `SiO_(2)` lies below the corresponding curve for `Mg, MgO `. Therefore, above 1966 K` can reduce `MgO` to `Mg`
`SiO_(2)+2MgOoverset(gt 1966 K)to SiO_(2)+2Mg`
(4) According to Ellinghere, the `DEElta_(T)G of CO_(2)` from `CO` is always highter that of `Delta_(T) G of ZnO` Therefoer `CO` con't the uses (or reduction of `ZnO` in `Zn` can be reduced to `Zn` by `C` .This clarly shown that , and of `C` and `CO , C `is a better reducting agent than `CO` for reduction of `ZnO to Zn`
In actual praction reduction is resulting corried our around `1673 K` so that the reduction process essetially given to completion