Choose the correct structure of D-D-xylose. 4. Below is a Haworth formula for an aldopentose. Give the name of the acyclic isomer. Your answer should contain capital D or L followed by a dash, and the name in lowercase letters (no space in between). 5. Which of the four D-aldopentoses give optically inactive alditols upon reduction with NaBH4? A. D-ribose and D-arabinose B. D-ribose and D-xylose C. D-ribose and D-lyxose D. D-arabinose and D-xylose E. D-arabinose and D-lyxose F. D-xylose and D-lyxose
6. Which pair of the four D-aldopentoses give the exact same aldaric acid when oxidized by HNO3?