Hydrogen



  • 0_1545826601149_IMG_20181226_174611.jpg
    Here assertion is true but reason is false please explain how



  • @sri
    30% solution of H2O2 is marketed as ‘100 volume " which means 30% solution of H2O2 is same as 100 mL solution of H2O2 .It is because the strength of H2O2 in both the solutions is same.

    H2O2 sold in the market is never 100% pure. The strength of a dilute solution of H2O2 is expressed as percent strength and also as volume strength.

    i. Percent strength: It represents the amount of H2O2 by mass in 100mL of solution. 30% solution means that 30 gram of H2O2 are present in 100 mL of solution.

    ii. Volume strength: It represents the concentration of H2O2 solution in terms of the volume of oxygen which is a solution of H2O2 gives on decomposition by heat.

    A 100 volume solution means that 1mL of H2O2 solution at STP will give 100 mL of oxygen gas on decomposition. If we convert volume strength into percentage strength,

    then 2H2O2 ---------> 2H2+O2

    2(2x1+2x16) 22400mL at STP From equation,

    22400 mL of O2 at STP is obtained by H2O2= 68g

    100mL O2 at STP is obtained by H2O2 = 68 x 100/22400 g = 0.3g ……….(i)

    Now given is 100 Volume solution i.e volume strength of H2O2 solution=100 volume

    which means 100mL of O2 is evolved by 1mL of H2O2 on decomposition.

    From equation(i), 1mL H2O2 solution will weigh= 0.3g

    100 mL H2O2 solution will weigh=0.3 x100=30g

    Percent strength of H2O2 solution =(weight of H2O2 / Volume of solution)x100

    = (30/100)x100 = 30%

    So, we can see that 100 volume solution of H2O2 is coming out to be equal to 30% solution of H2O2 solution.


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