Question

The coefficients p, q, r, s in the reaction pCr2o2- +qFe2- rCr2+ +sFe3+ +H2O
respectively are
(a) 1, 2, 6, 6
(b) 6, 1, 2,4
JE 1, 6, 2, 6
(d) 1, 2, 4, 6 24ho
For the following redey reactions find the CORRECT statement​

Answer 1

The coefficients p, q, r, s in the given reaction are (option C) 1, 6, 2, 7 respectively.

here we have a redox reaction between $Fe^{2+}$ and $Cr_{2}O_{7} ^ {2-}$

the given reaction will take place in the acidic medium so we will add $H^{+}$

in the reactant side.

So the reaction without balancing will be:

$Fe^{2+}$  +  $Cr_{2}O_{7} ^ {2-}$ + $H^{+}$ ⇄  $Fe^{3+}$  +  $Cr ^{3+}$ + $H_2O$

We can see that the oxidation of Fe is taking place while the reduction of Cr is there.

We will balance the given reaction by the method of balancing a redox reaction in an acidic medium and we will get:

$6Fe^{2+}$  +  $Cr_{2}O_{7} ^ {2-}$ + $14H^{+}$ ⇄  $6Fe^{3+}$  +  $2Cr ^{3+}$ + $7H_2O$