Question

how many moles of electrons are required to reduce 1mol MnO4 to Mn^2+

Answer 1

\(\boxed{\boxed{\boxed{\color{red}{\huge\heartsuit\boxed{H}}\color{green}{\boxed{E}}\color{green}{\small\boxed{L}}\color{green}{\boxed{L}}\color{blue}{\huge\boxed{O}}\color{blue}{\huge\heartsuit}}}}\)

Answer 2

hii!!

Answer 3

is it MnO4^- or MnO4 ?

Answer 4

Is it this
http://prntscr.com/3sqn9p

Answer 5

no 64!!

Answer 6

uh-oh..i don knw y the heck its not opening

Answer 7

Anyways i'll show it for MnO4

Answer 8

i try attach the file again

Answer 9

Oxidation state of Mn in MnO4 is +8

Answer 10

???

Answer 11

I got ur pic, what's the meaning of downward sign ?

Answer 12

i also don't know

Answer 13

What is the answer 5 or 8 ?

Answer 14

MnO4- is permanganate, with a charge of -1. The oxidation state of Mn in MnO4- is +7 (each O is -2, so Mn balances all of the negative charges but 1, so that there is an overall -1 charge on MnO4). Mn2+ has an oxidation state of +2. To go from +7 to +2, you need 5 electrons. The answer should be D - not sure why it's crossed out.

If this is a photocopied practice exam from somewhere else, you need to be careful with anything written on it, particularly if it came directly from a student. Just because D is crossed out, doesn't mean that's right.

Answer 15

Does the downward sign means -ve charge ?
@matt101

Answer 16

I've never seen an arrow used like this before...I'd chalk it up to a typo lol

Answer 17

That's why i was confused. As much i remember its used to denote electron inside an orbital..LOL..i got it

Answer 18

Its an electron and not a typo

Answer 19

Oh yes it could be a downward spin...just weird to see it in this notation. The other thing I was just thinking was that it could be the manganate ion, MnO4^(2-), meaning the answer would be 4 electrons. Permanganate just appears so much more frequently in these kinds of questions in my experience.

Answer 20

an extra electron denotes a negative charge

Answer 21

yes 5 is the answer, one arrow means a single electron

Answer 22

Sounds good to me!

Answer 23

\(\color{green}{\huge\ddot\smile}\)

Answer 24

the answer given is also D but i don't know how to get it that why I asked it.. thank you for the clear explanation @Abhisar and @matt101 :)

Answer 25

\(\Huge\text{Anytime !}\)
\(\huge\ddot\smile\)

Answer 26

Guess we all learned something from this question :P Glad to help

Answer 27

That's the beauty of Openstudy !
\(\color{green}{\huge\ddot\smile}\)

Answer 28

Have a Nice day All !