Suppose that a 0.2 g/ml solution of (s)-ibuprofen in a 2 dm long cell rotates plane-polarized light +10°. what is the specific rotation for (s)-ibuprofen?

+25°

Explanation:

The formula for calculatin the specific rotation, α, is:

α=αobs÷(c×l)

αobs being the rotation observed

c is being the concetration(g/mL)

l being the path length(dm)

So it ends up being:

α=+10°/(0.2 g/mL×2 dm)= +10°×ml/0,4g×dm

α=25°

the answer is option a.

i think its 100.

hope this !