Help with these please

17. Which of the following compounds is not drawn in its most stable chair conformation? (HINT: Draw the respective ring-flipped conformers) st CI HO II 111 IV I (A) I (B) II (C) III (D) IV (E) V 18. Draw the 2 possible chair conformations of trans-1-ethyl-3-isopropylcyclohexane in the boxes provided below. Which conformation, if either, is more stable? Explain your reasoning. conformer 2 conformer 1 19. Which of the following statements is true? (A) In their preferred conformations, cis-1,2-dimethylcyclohexane is more stable than trans-1,2-dimethylcyclohexane. (B) In their preferred conformations, cis-1,3-dimethylcyclohexane is more stable than trans-1,3-dimethylcyclohexane. (C) In their preferred conformations, cis-1-tert-butyl-4-methylcyclohexane is more stable than trans-1-tert-butyl-4-methylcyclohexane. (D) In their preferred conformations, cis-1-ethyl-2-methylcyclohexane is more stable than trans-1-ethyl-2-methylcyclohexane. (E) All of the above statements are true. wse the following boxes to draw the 2 possible chairs for cis-1,3-dimethylcyclohexane. Which conformation, if either, is more stable? Explain. conformer 1 conformer 2