Question

0.5 g of optically-enriched (-) mandelic acid was dissolved in 10 mL of absolute ethanol. Using a 1 dm polarimeter tube, the observed optical rotation was found to be -6.8° . What is the specific rotation?

Pure (-) mandelic acid has a specific rotation of -160 ° (same conditions and temperature as sample above). What is the % optical purity of the sample above?

3.5 mg of optically-enriched(-) sugar P was dissolved in 1.00 mL methanol in a 1.00 mL volumetric flask. The optical rotation was found to be -0.0222° in a 5.0 cm cell. What is the specific rotation? Show all your work please.