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If the density of some lake water is 1.25 g mL^(-1)and contains 92 g of Na^+ ions per kg of water, calculate the molarity of Na^+ions in the lake. |
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Answer» Solution : Number of moles in 92 g of `Na^+`IONS ` = (92 g)/(23 g "mol"^(-1)) = 4` mole (as atomic mass of Na = 23) Volume of 1000 g (1 kg) of solution = ` = (1000)/(1.25)= 800 ML^(-1)` Number of moles of `Na^+`in 1000 `mL^(-1)`of solution = ` 4/800 xx 1000 = 5 `moles Molarity = 5M |
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