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Which of the following concentrations of `NH_(4)^(+)` will be sufficient to prevent the precipitation of `Mg(OH)_(2)` form a solution which is 0.01 M `MgCl_2` and `0.1 M NH_3(aq.)` Given that :`K_(SP)` of `Mg(OH)_(2)=2.5xx10^(-11)` and `K_b` for `NH_3(aq)=2xx10^(-5)`A. 0.01 MB. 0.02 MC. 0.001 MD. 0.04 M |
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Answer» Correct Answer - D `K_(SP)=[Mg^(+2)][OH^(-)]^2` `[OH^(-)]=sqrt((2.5xx10^(-11))/0.01)=5xx10^(-5)` `K_b=([NH_4^+][OH^(-)])/([NH_3])` So, `[NH_4^+]=0.04 M` |
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