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Câu hỏi: Cho sơ đồ chuyển hóa các hợp chất của crom:
$Cr{{\left( OH \right)}_{3}}\xrightarrow{+KOH}X\xrightarrow{+\left( C{{l}_{2}}+KOH \right)}Y\xrightarrow{+{{H}_{2}}S{{O}_{4}}}Z\xrightarrow{+\left( FeS{{O}_{4}}+{{H}_{2}}S{{O}_{4}} \right)}T$
Các chất X, Y, Z, T theo thứ tự là:
A. $KCr{{O}_{2}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},{{K}_{2}}Cr{{O}_{4}},CrS{{O}_{4}}$
B. ${{K}_{2}}Cr{{O}_{4}},KCr{{O}_{2}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$
C. $KCr{{O}_{2}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},{{K}_{2}}Cr{{O}_{4}},C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$
D. $KCr{{O}_{2}},{{K}_{2}}Cr{{O}_{4}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$
$Cr{{\left( OH \right)}_{3}}\xrightarrow{+KOH}X\xrightarrow{+\left( C{{l}_{2}}+KOH \right)}Y\xrightarrow{+{{H}_{2}}S{{O}_{4}}}Z\xrightarrow{+\left( FeS{{O}_{4}}+{{H}_{2}}S{{O}_{4}} \right)}T$
Các chất X, Y, Z, T theo thứ tự là:
A. $KCr{{O}_{2}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},{{K}_{2}}Cr{{O}_{4}},CrS{{O}_{4}}$
B. ${{K}_{2}}Cr{{O}_{4}},KCr{{O}_{2}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$
C. $KCr{{O}_{2}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},{{K}_{2}}Cr{{O}_{4}},C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$
D. $KCr{{O}_{2}},{{K}_{2}}Cr{{O}_{4}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$
(1) $Cr{{\left( OH \right)}_{3}}+KOH\xrightarrow{{}}KCr{{O}_{2}}+2{{H}_{2}}O$
(2) $KCr{{O}_{2}}+C{{l}_{2}}+3KOH\xrightarrow{{}}{{K}_{2}}Cr{{O}_{4}}+2KCl+{{H}_{2}}O$
(3) $2{{K}_{2}}Cr{{O}_{4}}+{{H}_{2}}S{{O}_{4}}\xrightarrow{{}}{{K}_{2}}C{{r}_{2}}{{O}_{7}}+{{K}_{2}}S{{O}_{4}}+{{H}_{2}}O$
(4) ${{K}_{2}}C{{r}_{2}}{{O}_{7}}+7{{H}_{2}}S{{O}_{4}}+6FeS{{O}_{4}}\xrightarrow{{}}{{K}_{2}}S{{O}_{4}}+C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}+3F{{e}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}+7{{H}_{2}}O$
Vậy các hợp chất của crom là X, Y, Z, T theo thứ tự $KCr{{O}_{2}},{{K}_{2}}Cr{{O}_{4}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$
(2) $KCr{{O}_{2}}+C{{l}_{2}}+3KOH\xrightarrow{{}}{{K}_{2}}Cr{{O}_{4}}+2KCl+{{H}_{2}}O$
(3) $2{{K}_{2}}Cr{{O}_{4}}+{{H}_{2}}S{{O}_{4}}\xrightarrow{{}}{{K}_{2}}C{{r}_{2}}{{O}_{7}}+{{K}_{2}}S{{O}_{4}}+{{H}_{2}}O$
(4) ${{K}_{2}}C{{r}_{2}}{{O}_{7}}+7{{H}_{2}}S{{O}_{4}}+6FeS{{O}_{4}}\xrightarrow{{}}{{K}_{2}}S{{O}_{4}}+C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}+3F{{e}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}+7{{H}_{2}}O$
Vậy các hợp chất của crom là X, Y, Z, T theo thứ tự $KCr{{O}_{2}},{{K}_{2}}Cr{{O}_{4}},{{K}_{2}}C{{r}_{2}}{{O}_{7}},C{{r}_{2}}{{\left( S{{O}_{4}} \right)}_{3}}$
Đáp án D.