Question

0.2 moles of hydrochloric acid are dissolved in water to make a 500 mL solution. The molarity of the $C{l}^{-}$ ions is __.

• A. 0.60 M
• B. 0.20 M
• C. 0.80 M
• D. 0.40 M

Answer 1

The correct option is D 0.40 M

$\text{Molarity}=\frac{\text{moles of HCl}}{\text{total volume of solution (mL)}}\times 1000=\frac{0.2}{500}\times 1000=0.4M$

$HCl\to H^{+}+C{l}^{-}$
1 mole of $HCl$ gives 1 mole of $C{l}^{-}$,
0.4 M will give 0.4 M of $C{l}^{-}$.