How many grams of potassium dichromate a...

How many grams of potassium dichromate are required to oxidise 20.0 g of `Fe^(2+)` in `FeSO_(4)` to `Fe^(3+)` if the reaction is carried out in an acidic medium ? (Molar mass of `K_(2)Cr_(21)O_(7)` and `FeSO_(4))` are 294 and 152 respectively

Text Solution

Verified by Experts

The correct Answer is:

`6.45`

`Kr_(2)Cr_(2)O_(7)+4H_(2)SO_(4)rarrK_(2)SO_(4)+Cr_(2)(SO_(4))_(3)+4H_(2)O+3[O]`
`2FeSO_(4)+H_(2)SO_(4)+OrarrFe_(2)(SO_(4))_(3)+H_(2)Oxx3`
balanced redox reaction
`K_(2)Cr_(2)O_(7)+6FeSO_(4)+7H_(2)SO_(4)rarrK_(2)SO_(4)+Cr_(2)(SO_(4))_(3)+3Fe_(2)(SO_(4))_(3)+7H_(2)O`
It is evident from balanced equation that 6 moles of `FeSO_(4)=1` mole of `K_(2)Cr_(2)O_(7)`
`therefore` 20 g of `FeSO_(4)` will require `K_(2)Cr_(2)O_(7)`
`=(294)/(6xx152)xx20=6.45 g`

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How many grams of potassium dichromate are required to oxidise 20.0 g of Fe^(2+) "in" FeSO_(4) "to" Fe^(3+) if the reaction is carried out in acidic medium? Molar masses of K_(2)Cr_(2)O_(7) "and" FeSO_(7) are 294 and 152 respectively

6.45 g

7.45 g

8.45 g

9.45 g

How many germs of K_(2)C_(7)O_(7) are required to oxidise 20.0g of Fe^(+) ion in FeSO_(4) "to" Fe^(3+) ions if the reaction is carried out in the acidic medium? Molar mass of K_(2)Cr_(2)O_(7) and FeSO_(4) are 294 and 152 respectively.

6.45g

7.45g

8.45g

9.45g

The weight in grams of K_(2)Cr_(2)O_(7) required to oxidise Fe_(21) ions present in 7.6 gram of FeSO_(4) to Fe^(3+) if the reaction is carried out in an acidic medium is

`4.9` grams

`15.2` grams

`2.45` grams

`7.6` grams