A currrent of 5.0 A flows for 4.0 h through an electrlytic cell containing a molten salt of metalM. This results in deposition of 0.25 mol of the metal M at the cathode. The oxidation state of M in the molten salt is : (1 Faraday=`96485 C "mol"^(-1)`)

Options

A. `1 +`
B. `2 +`
C. `3 +`
D. `4 +`

Answer

C

Explanation

According to Faraday.s first law of electrolysis `W = (E xx ixx t)/(96500)`
Where E = equivalent weight
=` ("mol., mass of metal (M)")/("oxidation state of metal (x)")`
Substituting the value in the formula
`W = (M)/(x) xx (ixx t)/(96500)`
or `x = (M)/(W) xx (i xx t)/(96500) = (10 xx 2 xx 60 xx 60)/(96500 xx 0.250) = 3`
[Given : no. of moles = `(M)/(W) = 0.250`]
Hence oxidation state of metal is `(+3)`