If 200. ml of 0.60 m mgcl2(aq) is added to 400 ml of distilled water, what is the concentration of mg and cl in the resulting solution?
a. 0.20 m mg ion & 0.20 m cl ionb. 0.40 m mg ion & 0.40 m cl ionc. 0.20 m mg ion & 0.40 m cl iond. 2.0 m mg ion & 2.5 m cl ion

C. 0.20 M Mg ion & 0.40 M Cl ion

Explanation:

MgCl₂ is a ionic salt which is dissociated as this

MgCl₂  →  Mg²⁺  +  2Cl⁻

First of all, we have a solution of 200 mL, with [MgCl₂] = 0.6M

Molarity . volume = moles.

0.6 mol/l . 0.2l = 0.12 mol

  MgCl₂  →  Mg²⁺  +  2Cl⁻

0.12mol      0.12         0.24

This moles are also in 400mL of water, so the new concentration is

[Mg²⁺] = 0.12 m/0.6L = 0.2M

[Cl⁻] = 0.24 m/0.6L = 0.4M

Remember we initially have 200mL and then, we add 400 mL, so we supose aditive volume. (600mL)

The concentration of magnesium ion, Mg²⁺ in the resulting solution is 0.2 M while that of the chloride ion, Cl¯ is 0.4 M

The correct answer to the question is Option C. 0.20 M Mg ion & 0.40 M Cl ion

we'll begin by calculating the molarity of the diluted solution. This can be obtained as follow:

Volume of stock solution (V₁) = 200 mL

Molarity of stock solution (M₁) = 0.60 M

Volume of diluted solution (V₂) = 200 + 400 = 600 mL

The molarity of the diluted solution can be obtained as follow:

0.6 × 200 = M₂ × 600

120 = M₂ × 600

Divide both side by 600

M₂ = 120 / 600

Thus, the molarity of the diluted (i.e resulting) solution of MgCl₂ is 0.2 M

Next, we shall determine the concentration of magnesium ion, Mg²⁺ in the diluted solution. This is illustrated below:

MgCl₂(aq) —> Mg²⁺(aq) + 2Cl¯(aq)

From the balanced equation above,

1 mole MgCl₂ dissolves to produce 1 mole Mg²⁺.

Therefore,

0.2 M MgCl₂ will also produce 0.2 M Mg²⁺.

Thus, the concentration of magnesium ion, Mg²⁺ in the resulting solution is 0.2 M.

Finally, we shall determine the concentration of the chloride ion, Cl¯ in the resulting solution.

MgCl₂(aq) —> Mg²⁺(aq) + 2Cl¯(aq)

From the balanced equation above,

1 mole MgCl₂ dissolves to produce 2 moles of Cl¯

Therefore,

0.2 M MgCl₂ will also produce = 2 × 0.2 = 0.4 M Cl¯

Thus, the concentration of chloride ion, Cl¯ in the resulting solution is 0.4 M.

From the calculations made above:

The concentration of magnesium ion, Mg²⁺ in the resulting solution is 0.2 M while that of the chloride ion, Cl¯ is 0.4 M

Option C. 0.20 M Mg ion & 0.40 M Cl ion gives the correct answer to the question.

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