A 2.00 ml sample of an aqueous solution of hydrogen peroxide, H2O2 (aq) is treated with an excess of Kl (aq). The liberated I2 requires 12.40 mL of 0.1025 M Na2S2O3, for its titration. Is the H2O2 up to the full strength (3% H2O2 by mass) as an antiseptic solution? Assume the density of the aqueous solution of H2O2 ( aq) is 1.00 g/ mL.

H2O2(aq) + H + I^-(aq) ---> H20(l)+I2 (not balanced)

S203^2- + I2 ----> S406 ^2- (aq) + I^- (aq) (not balanced)

The balanced chemical equations are:

H2O2(aq) + 2H+(aq) + 2I-(aq) ---> 2H20(l) + I2

2S2032- + I2 ---> S4062-(aq) + 2I-(aq)

Moles of S2O3^2- = (0.01240L)(0.1025 mol/L) = 0.001271 S2O3^2-
Since 1 mole of I2 reacts with 2 moles of S2O3^2-,
(0.5)(0.001271mol S2O3^2-) = 0.0006355 moles I2
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1 mole of I2 is formed from 1 mole of H2O2
0.0006355 moles I2 is formed from 0.0006355 moles H2O2
(0.0006355 moles H2O2)(34g/mol) = 0.0216 g H2O2
(2.00 ml)(1.00g/mL) = 2.00g H2O2
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Now you have all the information needed to calculate the % of H2O2

To determine if the H2O2 solution is up to its full strength, we need to calculate the concentration of H2O2 in the solution.

First, we can calculate the number of moles of I2 using the volume and molarity of Na2S2O3:

moles of I2 = volume (L) x molarity (mol/L) = 12.40 mL x 0.1025 mol/L = 1.270 mol

Since the equation shows a 1:1 stoichiometry between H2O2 and I2, the number of moles of H2O2 must also be 1.270 mol.

Next, we can calculate the mass of H2O2 in the sample:

mass of H2O2 = moles x molar mass = 1.270 mol x 34.02 g/mol = 43.135 g

Now, we can calculate the mass percentage of H2O2 in the sample:

mass percentage of H2O2 = (mass of H2O2 / mass of sample) x 100

The mass of the sample is given as 2.00 mL of solution, and we can convert it to grams using the density of the solution:

mass of sample = volume x density = 2.00 mL x 1.00 g/mL = 2.00 g

mass percentage of H2O2 = (43.135 g / 2.00 g) x 100 = 2156.75%

The resulting mass percentage of H2O2 is 2156.75%, which is significantly higher than the expected concentration of 3% H2O2 by mass. Therefore, the H2O2 solution is not up to its full strength (3% H2O2 by mass) as an antiseptic solution.

Note: It is important to critically evaluate the obtained result, as an error may have occurred during the calculations or the given information could be incorrect.