question_answer

Which substance is serving as a reducing agent in the following reaction                 \[14{{H}^{+}}+C{{r}_{2}}O_{7}^{2-}+3Ni\to 2C{{r}^{3+}}+7{{H}_{2}}O+3N{{i}^{2+}}\] [CBSE PMT 1994; AFMC 2000; DPMT 2001]

A)                 \[{{H}_{2}}O\]  

B)                 \[Ni\]

C)                 \[{{H}^{+}}\]

D)                 \[C{{r}_{2}}O_{7}^{2-}\]