Redox Reactions And Electrochemistry Ques 766
Question: In the following reaction, $ As_2S_3+{{H}^{+}}+NO_3^{-}\xrightarrow{{}} $ $ NO+H_2O+AsO_4^{3-}+SO_4^{2-}, $ the equivalent weight of $ As_2S_3 $ is related to molecular weight by
Options:
A) $ \frac{M}{14} $
B) $ \frac{M}{28} $
C) $ \frac{M}{7} $
D) $ \frac{M}{10} $
Show Answer
Answer:
Correct Answer: B
Solution:
[b] Idea This problem is based on concept of n-factor determination and their equivalent wt. determination. Determine the n-factor first Then, equivalent wt. $ =\frac{\text{molecular wt}.}{\text{n-factor}} $
Oxidation state of As $ O_4^{3-}=x-2\times 4=-3 $ $ x-8=-3 $ $ x=5 $
Oxidation state of S in $ SO_4^{2-}=x-2\times 4=-2 $ $ x-2+8=+6 $
n-factor = Sum of positive oxidation states = Total oxidation state of $ 2AsO_4^{3-} $ + Total oxidation state of $ SO_4^{2-} $
$ =2\times 5+3\times 6=10+18=28 $ Equivalent wt. $ =\frac{M}{28} $
