1. Based on structure (figure 1), rank them in terms of increasing polarity for
ID: 520018 • Letter: 1
Question
1. Based on structure (figure 1), rank them in terms of increasing polarity for the organic compounds -Carotene, Alizarin Red (1,2-dihydroxyanthraquinone sulfonate), and Thymol Blue (note isopropyl groups). Explain your reasoning based on structure.
2. Calculate the polarity P' values for 2:1 hexane:isopropanol and compare to 100% methanol.
3. Calculate the polarity P' values for 3:1 water-methanol and compare to 100% isopropanol.
1. Based on structure (figure 1), rank them in terms of increasing polarity for the organic compounds -Carotene, Alizarin Red (1,2-dihydroxyanthraquinone sulfonate), and Thymol Blue (note isopropyl groups). Explain your reasoning based on structure.
2. Calculate the polarity P' values for 2:1 hexane:isopropanol and compare to 100% methanol.
3. Calculate the polarity P' values for 3:1 water-methanol and compare to 100% isopropanol. Water is a very polar molecule and oil or a hydrocarbon like hexane is considered very nonpolar, on the other end of the polarity scale. A quantitative polarity scale which includes most common solvents has been devised indicating the degree of polarity as P. For example, for 10.1 is highly polar and that for hexane 0.1 is very such as methanol, 5.1, isopropanol, P' 3.9, and toluene, P-2.4, fall in between these limits. For a mixture of solvents, P AB fAP A fBP'B where fA the fraction of solvent A, P A-polarity of A, fB fraction of solvent B, and P'B polarity of solvent B. In terms of structure, "like dissolves like". organic compounds with mostly C-H bonds such as aromatic groups are considered nonpolar and will be soluble in hexane or Organic compounds with a few polar atoms such as O or N or charged hexane-toluene groups have intermediate polarity and will be soluble in isopropanol or isopropanol-water mixtures. Organic compounds with many o and N and/or a few charged groups such as NH, Coo, or sos in the structure are quite polar and will be soluble in methanol-water or water. S-ONa OH OH SOs Alizarin Red Thymol blue CH CH CH A-carotene Figure 1. Structure of thymol blue, Alizarin Red, and B-carotene
Explanation / Answer
increasing order 1)alizarin 2)thymol blue3)b-carotene
reason-as we can observe its structure for alizarin as breakdown of double bonds for ketone group of oyxgen is in transational form and Na+ charge being lewis base water polar nature,next coming to thymol blue a ketone group and hydroxy groupan and coming to caotene stucture it has long duble bond chain which is not that easily breakable.
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