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# What is the molarity of solution, if 60g of $Co(NO_3)_2.6H_2O$ dissolved in 4.3L of solution.(m.wt=260) ?

$\begin{array}{1 1}(a)\;0.05M\\(b)\;0.1M\\(c)\;0.15M\\(d)\;0.20M\end{array}$

Molarity (M) is defined as number of moles of solute dissolved in one litre (or one cubic decimetre) of solution, $M = \large\frac{\text{ Moles of solute }}{\text{Molarity Volume of solution in litre}}$
Given, Volume of solution in litre $= 4.3\;L$
Molar mass of $Co(NO_3)_2.6H_2O = 59+2\times (14+3\times 16)+6\times18=291\;g\;mol^{-1}$
Therefore number of moles of solute $= \large\frac{60}{291} $$= 0.206\;mol \Rightarrow Molarity M = \large\frac{0.206\;mol}{4.3\;L}$$= 0.047\;M$
edited Jul 16, 2014