How many millimoles of potassium dichromate is required to oxidise 24 ml of 0.5 M Mohr salt solution in acidic medium ?

Answer

2 Milimols

Explanation

No Of millimoiles of `K_(2)Cr_(2)O_(7)` present in 24 mL Of 0.5 M solution =`24xxx0.5=12`
The balanced chemical eqaution for the redox reaction is
`K_(2)Cr_(2)O_(7)+6(NH_(4))SO_(4).FeSO_(4).6H_(2)O+7H_(2)SO_(4)rarrK_(2)SO_(4)+6(NH_(4))SO_(4)+3Fe_(2)(SO_(4))_(3)+Cr_(2)(SO_(4))_(3)+43H_(2)O`
From the balanced eqaution 6 moles Mohr salt are oxidised by `K_(2)Cr_(2)O_(7)` =1 Mole
`therefore` 12 millimoles of Mohr 's salt will be oxidised by `K_(2)Cr_(2)O_(7)=(1)/(6)xx12=2` millimoles