A) Zinc can be oxidised by CO
B) Zinc oxide can be reduced by carbon
C) Both (a) and (b)
D) None of the above
Correct Answer: B
Solution :
\[2Zn+2C\xrightarrow{{}}2Zn+2CO,\Delta {{G}^{o}}=-100\,kJ/mol\] Hence, this is spontaneous. During reduction of a metal oxide, reducing agent forms its oxide. The role of reducing agent is to provide \[{{\Delta }^{o}}G\] negative and large enough to make the sum of \[{{\Delta }^{o}}G\] of the two reactions (oxidation of the reducing agent and reduction of the metal oxide) negative. Now, for the given reactions \[{{\Delta }^{o}}G\] is provided for the oxidation of carbon and zinc. To get \[{{\Delta }^{o}}G\] for the reduction of \[ZnO,\] equation-(ll) has to be reversed as follows- \[2ZnO\xrightarrow{{}}2Zn+{{O}_{2}}\,;{{\Delta }^{o}}G=+360\,\,kJ\,mo{{l}^{-1}}\] Positive value of \[{{\Delta }^{o}}G\] shows that it is a non-spontaneous process. But this reaction can be drive to the spontaneity by coupling it with first reaction. \[2ZnO+2C\xrightarrow{{}}2CO+2Zn\] \[{{\Delta }^{o}}G=-460+360=-100\,\,kJmo{{l}^{-1}}\]
You need to login to perform this action.
You will be redirected in
3 sec
