The domestic water supply is treated by bleaching powder to remove unhygienic species in water and to make it safe for drinking water. However, this given rise to `Ca^(2+)` and `Cl^(-)` ion contamination in water. Both these ions are also injurious for health if a minimum concentration is crossed. The chloride ions are tested by a kit provided by many companies having `AgNO_(3)` solution that is added drop by drop to `23 mL` of water sample to which an indicator has been added. When sufficient silver nitrate is added to remove `Cl^(-1)` ions as `AgCl` solid, the solid turns orange. The colour change is noticed by addition of `AgNO_(3)` having molar concentration such that each drop `(0.05 mL)` of `AgNO_(3)` converts `12.5 mg` of `Cl^(-)` ions `AgCl`.
The molar concentration of `AgNO_(3)` solution if one drop of `AgNO_(3)` measure `0.05 mL` is:

Options

A. `6.04xx10^(-3)M`
B. `7.04xx10^(-3)M`
C. `150 M`
D. `3.52 M`

Answer

B

Explanation

`1 "drop" AgNO_(3)= 0.05 mL AgNO_(3)`
`therefore 12 "drop" AgNO_(3)=0.05xx12 mL AgNO_(3)`
`= 0.60 mL AgNO_(3)`
`mM "of" AgNO_(3)` in `12 "drop" = mM "of" Cl^(-)` in `23 mL` sample
`Mxx0.6=(150xx10^(-3))/(35.5)`
`therefore M=7.04xx10^(-3)`