question_answer

Consider the following equation, which represents a reaction in the extraction of chromium from its ore \[2F{{e}_{2}}{{O}_{3}}.C{{r}_{2}}{{O}_{3}}+4N{{a}_{2}}C{{O}_{3}}+3{{O}_{2}}\] \[\xrightarrow{{}}2F{{e}_{2}}{{O}_{3}}+4N{{a}_{2}}Cr{{O}_{4}}+4C{{O}_{2}}\] Which one of the following statements about the oxidation states of the substances is correct?

A)  The iron has been reduced from \[+3\] to \[+2\] state.

B)  The chromium has been oxidised from \[+3\] to \[+6\] state.

C)  The carbon has been oxidised from \[+2\] to \[+4\] state.

D)  There is no change in the oxidation state of the substances in the reaction.