Question

The observed rotation of 2.0 gg of a compound in 50 mLmL of solution in a polarimeter tube 25-cmcm long is +47.2 ∘∘ . What is the specific rotation of the compound?

Answer 1

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!