Question

if 1.8 L of water is added to 2.5L of a 7.0 M KOH solution, what is the molarity of the new solution

Answer 1

Answer : The molarity of the new solution is, 4.069 M

Solution : Given,

Molarity of KOH solution = 4 M

Volume of KOH solution = 2.5 L

Volume of water added = 1.8 L

First we have to calculate the volume of new solution.

Volume of new solution = volume of KOH solution + volume of water added

Volume of new solution = 2.5 L + 1.8 L = 4.3 L

Now we have to calculate the molarity of the new solution.

Formula used :

$M_1V_1=M_2V_2$

where,

$M_1$ = molarity of KOH solution

$M_2$ = molarity of new solution

$V_1$ = volume of KOH solution

$V_2$ = volume of new solution

Now put all the given values in the above formula, we get the molarity of the new solution.

$(7M)\times (2.5L)=M_2\times (4.3L)$

$M_2=4.069M$

Therefore, the molarity of the new solution is, 4.069 M