Question

1a.) The specific rotation, [α]_D, for (-)-pseudoephedrine is -52. What is the observed rotation for a solution of 0.70 g of (-)-pseudoephedrine in 10 mL of water in a sample tube having a pathlength of 10 cm?

The observed rotation of a solution of 0.75 g of a compound in 10 mL of water is -4.6 degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?

1b.) The specific rotation, [α]_D, for (-)-2-butanol is +14. What is the observed rotation for a solution of 2.5 g of (-)-2-butanol in 10 mL of water in a sample tube having a pathlength of 10 cm?

The observed rotation of a solution of 1.3 g of a compound in 10 mL of water is +3.7 degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?

1c.)The specific rotation, [α]_D, for (+)-alanine is +8.5. What is the observed rotation for a solution of 1.7 g of (+)-alanine in 10 mL of water in a sample tube having a pathlength of 10 cm?

The observed rotation of a solution of 1.3 g of a compound in 10 mL of water is +11 degrees. If the pathlength is 10 cm, what is the specific rotation of the compound?

Answer 1

specific rotation = a/l*c
l is in dm
c is in gm/mL
a is in degree

1a)i)
here:
a = ?
l = 10 cm = 1 dm
c = 0.70 g / 10 mL = 0.07 g/mL
specific rotation = a/l*c
-52 = a/(1*0.07)
a = -3.64 degree
Answer: -3.64 degree

1a)ii)
here:
a = -4.6 degree
l = 10 cm = 1 dm
c = 0.75 g / 10 mL = 0.075 g/mL
specific rotation = a/l*c
= -4.6/(1*0.075)
= -61.3
Answer: -61.3

Rest of the questions are not related to above 2 questions that I have answered
I am allowed to answer only 1 question at a time