Question

A solution containing 0.2 g/mL of a pure R enantiomer in a 1 dm polarimeter rotates plane polarized light by +3°. What is the specific rotation of the R isomer?

a. +0.6°
b. +15°
C. +67°
d. +150°

Answer 1

The specific rotation of the R isomer is +15°.

Step-by-step explanation:

The specific rotation of the R isomer can be calculated using the formula:

Specific Rotation ([a]) = observed rotation / (concentration * path length)

In this case, the observed rotation is +3°, the concentration is 0.2 g/mL, and the path length is 1 dm (which is equivalent to 10 cm).

Plugging in the values, we get:

[a] = +3° / (0.2 g/mL * 10 cm) = +15°

Therefore, the specific rotation of the R isomer is +15°.