Question

what is the molarity of the resulting solution when 400. ml of a 0.400 m solution is diluted to 800. ml?
1.20 m
0.800 m
0.200 m
0.133 m

Explanation:

Step1: Use dilution formula

The dilution formula is \(M_1V_1 = M_2V_2\), where \(M_1\) is the initial molarity, \(V_1\) is the initial volume, \(M_2\) is the final molarity, and \(V_2\) is the final volume.
Given \(M_1=0.400\space M\), \(V_1 = 400\space mL\), \(V_2=800\space mL\).
We need to find \(M_2\).
From \(M_1V_1 = M_2V_2\), we can express \(M_2=\frac{M_1V_1}{V_2}\).

Step2: Substitute values

Substitute the values into the formula:
\(M_2=\frac{0.400\space M\times400\space mL}{800\space mL}\)
\(M_2=\frac{160}{800}\space M\)
\(M_2 = 0.200\space M\)

Answer:

\(0.200\space M\) (the third option)