chem (2)

The chemical equation:

2H2(g) + O2(g) → 2H2O(l)

So, molar ratio of H2 : O2 : H2O = 2 : 1 : 2

Molar mass of H2O

= 1.0 X 2 + 16.0

= 18.0 gmol^-1

Hence, number of mole of H2O

= mass / molar mass

= 18 / 18.0

= 1 mole

Therefore, to produce 18 g of H2O, at least 1 mole of H2 and 0.5 mole of O2 is needed.


For (1): no. of mole of H2 = 10 / 2 = 5 moles

no. of mole of O2 = 10 / 32 = 0.3125 mol < 0.5 mole

So, O2 is the limiting agent. The amount of H2O produced depends on the amount of O2. But not enough O2 is present for producing 18 g of H2O.

So, (1) is wrong.


For (2): no. of mole of H2 = 2 / 2 = 1 mol

no. of mole of O2 = 18 / 32 = 0.5625 mol > 0.5 mol

So, H2 is the limiting agent, the amount of H2O produced depends on the amount of H2. And 1 mole of H2O (which corresponds to 18 g) is produced. So, this is correct.


For (3): no. of mole of H2 = 4 / 2 = 2 moles

no. of mole of O2 = 16 / 32 = 0.5 mol

Now, O2 is the limiting agent, the amount of H2O produced depends on the amount of O2. And 1 mole of H2O (which corresponds to 18 g) is produced. So, this is correct.


Therefore, statements 2 and 3 are correct.