Question

what is the oxidation number of chromium in Na2 Cr2 O7

Answer 1

Answer:

Let oxidation number of Cr be X

2(+1)+2x+7(-2)=0

⇒ 2x+2=14

⇒ 2x=12

⇒ X=+6

Thus oxidation number of chromium(Cr) is +6

Answer 2

$\ Na_2Cr_2O_7$

Let the oxidation number of chromium be 'x'

☆ Oxidation number of Na is +1

☆ Oxidation number of O is -2

➡️ 2(+1) + 2x + 7(-2) = 0

➡️ 2 + 2x - 14 = 0

➡️ 2x - 12 = 0

➡️ 2x = 12

➡️ x = 12/2

➡️ x = 6

So, the oxidation number of chromium is +6