The question is incomplete, the complete question is:
If a 6.00 g sample of an optically pure compound was dissolved in 40.0 mL of [tex]CCl_4[/tex] and the observed rotation was +3.30°, measured in a 10.0 cm (1.00 dm) polarimeter tube, how would one determine the specific rotation of the pure compound?
Answer: The specific rotation of the pure compound is [tex]+22^o[/tex]
Explanation:
To calculate the specific rotation of a pure compound, we use the equation:
[tex][\alpha]=\frac{\alpha_{\text{observed}}}{C\times l\text{( in dm)}}[/tex]
where,
[tex][\alpha][/tex] = specific rotation of a pure compound
[tex]\alpha_{\text{observed}}[/tex] = observed rotation of the compound = [ex]+3.30^o[/tex]
C = concentration in g/mL = 6.00 g/40 mL = 0.15 g/mL
l = path length = 1.00 dm
Putting values in above equation, we get:
[tex][\alpha]=\frac{+3.30^o}{0.15\times 1.0}[/tex]
[tex][\alpha]=+22^o[/tex]
Hence, the specific rotation of the pure compound is [tex]+22^o[/tex]
