Question

9 calculate the equivalent weight of each oxident and reductant

. As2S3 + HNO3 =
H2ASO4 + H2SO4 + NO​

Answer 1

Answer

First, I think there is a typing mistake…. it should be AsO3−4AsO43− instead of AsO−4AsO4−…….

Second, I hope you know that equivalent weight = MMNfMMNf

and

that this is a redox involving multiple oxidation ……

Also

Nf=∑(ΔOS)Nf=∑(ΔOS)

that actually means we need to add all the changes in oxidation states

NO−3+As2S3→AsO3−4+NO+SO2−4NO3−+As2S3→AsO43−+NO+SO42−

Oxidation state of As before and after the reaction is +3 and +5

and

That of S is -2 and 6

Now, NfNf = (2x2)forAs+(8x3)forS=28(2x2)forAs+(8x3)forS=28

equivalent wt of As2S3As2S3 = MM28MM28

Hope this helps.

Answer 2

Answer:

Answer is 123.01g/equivalent

Explanation:

This is a redox reaction , so in order to determine the equivalent weight in this type or reactions, we have to follow this equations:

Eq. wt, of OA= molecular wt./ no. of e- gained by one molecule

                     = molecular wt./ change in ON per mole

Eq. wt. of RA= molecular wt./ no, of e- lost by one molecule

                    = molecular wt./ change in ON per mole

where; O.A is an oxidizing agent and R.A is a reducing agent.

First, we can obtain the molecular weight of Arsenic sulfide from the Periodic Table of elements which is 246.02g/mol .

Second, we have to follow the change in oxidation number of As before the reaction and after it to determine the valency.

-As a reactant , the oxidation number of As in As2S3 is (+3)

-As a product , the oxidation number of As in (AsO4)-3 is (+5)

Hence, the change in oxidation number is 2 which is the absolute difference between them.

By substitution in the equation, the equivalent weight of As2S3 is 123.01g/equivalent .