# Which solution contains the biggest amount, in mol, of chloride ions? A. 20 cm3 of 0.50 mol dm−3 NH4Cl B. 60 cm3 of 0.20 mol dm−3 MgCl2 C. 70 cm3 of 0.30 mol dm−3 NaCl D. 100 cm3 of 0.30 mol dm−3 ClCH2COOH

May 9, 2017

I make it $\left(B\right)$........

#### Explanation:

And to answer the question, we must calculate the molarity of of each solution with respect to chloride ions.

And $\text{number of moles"="concentration"xx"volume}$

For $\left(a\right) :$ there are $0.020 \cdot {\mathrm{dm}}^{3} \times 0.50 \cdot m o l \cdot {\mathrm{dm}}^{-} 3 = 0.01 \cdot m o l$.

For $\left(b\right) :$ $0.060 \cdot {\mathrm{dm}}^{3} \times 0.20 \cdot m o l \cdot {\mathrm{dm}}^{-} 3 \times \text{2 equiv} = 0.024 \cdot m o l$.

For $\left(c\right) :$ $0.070 \cdot {\mathrm{dm}}^{3} \times 0.30 \cdot m o l \cdot {\mathrm{dm}}^{-} 3 = 0.021 \cdot m o l$.

For $\left(d\right) :$ THERE ARE NO CHLORIDE IONS IN SOLUTION. Why not?

Why did I double the quantity in $\left(b\right)$?