Question

`0.1` millimole of `CdSO_(4)` are present in 10 mL acid solution of `0.08N HCI`. Now `H_(2)S` is passed to precipitate all the `Cd^(2+)` ions. The pH of the solution after filtering off precipitate, boiling of `H_(2)S` and making the solution 100 mL by adding `H_(2)O`, is:
A. 2
B. 4
C. 6
D. 8

Answer 1

Correct Answer - A
`{:(,CdSO_(4)+,H_(2)Soverset(HCI)rarr,CdS+,H_(2)SO_(4)),("Millimoles added", 0.1,10xx0.08, ,),(, ,=0.8, ,),("Millimoles after reaction", 0,0.8,0.1,0.1):}`
Millimole of `H^(+)l eft = 0.8+0.1xx2=1.0`
`(f rom HCI)(f rom H_(2)SO_(4))`
Total volume = 100 mL.
`:. [H^(+)]= (1)/(100)=10^(-2)M`
`:. pH=2`