Answer:
The final concentration is 0.288 M (approximately)
Explanation:
Using dilution formula:
C1V1 = C2V2
Where C1 is the initial concentration
C2 is the final concentration
V1 is the initial volume
V2 is the final volume
In the first dilution, C1 = 1.8M,
V1 =71mL, V2 = 218mL from the formula C2 = 1.8 ×71/281
=0.5862M
In the second dilution,
C1 = 0.5862M, V1 = 109mL, V2 = 222 mL (109+113)
C2 = 0.5862 × 109 ÷ 222
= 0.288 M (approximately) assuming volume is additive.