Molarity (M) is a unit of concentration in solutions. If a solution has a molarity of 2, we would identify it as 2M, and we say it is 2 molar. M means mol/L. So a 2M solution has a concentration of 2 mol/L.
The formula that allows you to answer this question is:
#M_1V_1=M_2V_2#
where #M_1# and #M_2# are the molarity of the solutions in mol/L, and #V_1# and #V_2# are the volume of the solutions in liters.
Known
#M_1="12.0 mol/L"#
#M_2="1.0 mol/L"#
#V_2="2.0 L"#
Unknown : #V_1#
Solution
Rearrange the equation to isolate #V_1#. Substitute the known values into the equation and solve.
#V_1=(M_2V_2)/M_1#
#V_1=(1.0color(red)cancel(color(black)("mol"))/color(red)cancel(color(black)("L"))xx2.0"L")/(12.0color(red)cancel(color(black)("mol"))/color(red)cancel(color(black)("L"))##=##"0.17 L"# rounded to two significant figures
