Question

(On the verge of tears)

Answer 1

Answer: The final molarity of a 20mL- 1.3M salt solution after it has been diluted with 100ml water is 0.22 M

Explanation:

According to the dilution law,

$M_1V_1=M_2V_2$

where,  

$M_1$ = molarity of stock solution = 1.3  M

$V_1$ = volume of stock solution = 20 ml  

$M_1$ = molarity of diluted solution = ?

$V_1$ = volume of  diluted solution = (20+100) ml = 120 ml

Putting in the values we get:

$1.3\times 20=M_2\times 120$

$M_2=0.22M$

Therefore  the final molarity of a 20mL- 1.3M salt solution after it has been diluted with 100ml water is 0.22 M