Redox Reactions And Electrochemistry Ques 423
Question: The oxidation number of $ Cr $ in $ K_2Cr_2O_7 $ is [CPMT 1981, 85, 90, 93, 99; KCET 1992; BHU 1988, 98; AFMC 1991, 99; EAMCET 1986; MP PMT 1996, 99, 2002; MP PET/PMT 1998; Bihar CEE 1995; RPET 2000]
Options:
A) +6
B) - 7
C) +2
D) - 2
Show Answer
Answer:
Correct Answer: A
Solution:
$ \overset{*}{\mathop{K_2Cr_2O_7}}, $ $ 2+2x-2\times 7=0 $ ; $ 2x-14+2=0 $ $ 2x=12 $ ; $ x=\frac{12}{2}=+6 $ .
