question 18(chemistry)(both question)

Question

12.) Mole fraction of ethyl alcohol in aqueous ethyl alcohol solution is 0.25. Hence percentage of ethyl alcohol by weight is

13.) 35 ml sample of hydrogen peroxide gives off 500ml of o₂ at 27^oC and 1 atm pressure. Volume strength of H₂O₂ sample will be

Answer 1

(12) If ethanol is 0.25, then H2O will be 0.75.
Mol wt of ethanol is 46.06g/mol,
So, 0.25 mol=11.515g of ethanol

Mol wt of H2O is 18.01528g/mol,
So, 0.75 mol=13.51g of H2O

Total wt=25.02646g
wt % of etanol is = 11.515 / 25.02646 * 100 = 46.011%
Approximately 46%