Question

Find out Volume of `H_2`?

Find out the volume of `H_2` gas at STP when steam is passed over `5.6g` of hot iron.

Answer 1

`3.024` L

Explanation:

First we need to know the equation of the reaction undergoing.

`3Fe + 4H_2O(g) = Fe_3O_4 + 4H_2`

So, for 3 moles of red hot `Fe` reacting with 4 moles of steam, 4 moles of `H_2` gas is generated.

3 moles of `Fe` = `56 * 3` g = `168` g [Atomic weight of iron = 56]

4 moles of hydrogen = `4 * 2` g = `8` g

So, Using Unitary method,

`168` grams `Fe` `rarr` `8` g `H_2`

`1` gram `Fe` `rarr` `8/168` g `H_2`

`5.6` gram `Fe` `rarr` `(8 * 5.6)/168` g `H_2` `approx` `0.27` grams `H_2`

We know, 1 mole of Every gas at STP takes a volume of `22.4` L.

So, `2` g `H_2` `rarr` `22.4` L

`1` g `H_2` `rarr` `22.4/2` L

`0.27` g `H_2` `rarr` `11.2 * 0.27` L = `3.024` L

Hence Explained.