500 mL of 56 V H2O2 is kept in an open container due to which some H2O2 is decomposed and evolves 8gm O2 simultaneously, during the process some H2O also vapourizes. Due to all these changes final volume is reduced by 20%. Find final volume strength of H2O2 (aq).
56
44.8
11.2
33.6
Therefore, Vol of O2 produced by 500ml solution = 56*500ml = 28 L
Now, Moles of O2 produced = 28/22.4 = 1.25 mol
The chemical equation is given as follows:
Therefore from the stoichiometry calculations, we have:
1 mole of O2 will be produced by 2 moles H2O2
Therefore, 1.25 moles of O2 will be produced by 2.5 mol of H2O2
So, mass of H2O2 = 2.5*34= 85g
Now, the density of H2O2 = 170g/L
Again, as given in the question, the amount of O2 evolved = 8g or 0.25 mol
Hence 0.5 mol of H2O2 decomposes to produce 0.5 mol of H2O and 0.25 mol of O2
Loss = 20% of 85 g = mass of O2 escaped + mass of H2O vapourised
=> mass of H2O vapourised = 14.45 - 8 = 6.45 g
So final solution contains only H2O2
Mass of final solution = 85 - 14.45 = 70.55 g
Final vol = 70.55/170 = 415 ml
68g H2O2 gives 32g O2
=> 415 ml of solution gives 1.04 moles of O2 or 23296 ml O2
=> 1ml solution gives = 23296/415 = 56.1 ml of O2
Hence vol strength = 56.1 V
Therefore, Option (1) is correct