Answer:
[∝] = +472
Explanation:
Specific rotation in a solution is defined as:
[∝] = ∝ / c×l
Where:
[∝] is specific rotation, ∝ is observed rotation (In degrees), c is concentration in g/mL and l is path length (In dm).
∝: +47.2°
c: 2.0g / 50mL = 0.04g/mL
l: 25cm × (1dm /10cm) = 2.5dm
Replacing:
[∝] = +47.2° / 0.04g/mL×2.5dm = +472
I hope it helps!