Question

The amount of S present in steel samples can be determined by conversion of S to H2S which is
subsequently estimated by titration with I2. In this latter process I2 is reduced to I-ion. I2 solutions
used in volumetric analysis must be standardized prior to use, as I2 is volatile and the solutions decrease
in concentration with storage. One way of standardizing 12 solutions is by titrating it against a known
mass of Arsenic(III) oxide. In using this standardization method it is important to add NaHCO3 in
excess to the solution of Arsenic(III) oxide. In an analysis of sulphur a chemist standardizing an 12
solution finds that 10 ml of 12 solution reacts with exactly 0.04945 g of As2O3. Continuing the analysis
the chemist finds that the H2S liberated from a 5 g sample of steel requires 1.9 ml of I2 solution to reach
an end point.
If H2S and I2 react in an equimolar ratio, the equivalent weight of H2S is

a) 34/8
b) 34
c) 34/2
d) 34/6​

Answer 1

Answer:

The sulphur content of a steel sample is determined by converting it to

gas, absorbing the

in 10 mL of 0.005 M

and then back titrating the excess

with 0.002 M

. If 10 mL

is required for the titration , how many milligrams of sulphur are contained in the sample ? <br> Reactions :

Answer 2

Answer:

34/2

Explanation:

In the reaction the n-factor of H2S is 2

and molecular mass of H2S is 34

so equivalent weight of H2S when reacting in equimolar ratios is 34/n-factor

34/2