1.

Solubility product of silver bromide is 5.0xx10^(-13). The quantity of potassium bromide (molar mass taken as 120 g "mol"^(-1)) to beadded to 1 litre of 0.05M solution of silver nitrate to start the precipitation of AgBr is

Answer»

`6.2xx10^(-5) g`
`5.0xx10^(-8) g`
`1.2xx10^(-10) g`
`1.2xx10^(-9) g`

Solution :`[AG^(+)]=0.05 M `
`K_(SP)(AgBr)=[Ag^(+)][Br^(-)]`
`:. [Br^(-)]=(K_(sp))/([Ag^(+)])=(5.0xx10^(-13))/(0.05)=10^(-11)M`
i.e., amount of KBR to be added`=10^(-11)` MOLE
`=10^(-11)xx120 g = 1.2 xx 10^(-9) g`.


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