Hello! I have a few questions related to NMR that I would love clarification on, thank you so much!


   

Quote from: amimi on February 17, 2026, 12:46:38 AMHello! I have a few questions related to NMR that I would love clarification on, thank you so much!

In aromatic rings:

ortho coupling (adjacent H's) is the largest → typically ~6–9 Hz

meta coupling is smaller → typically ~1–3 Hz

para coupling is very small (often ~0–1 Hz)
From the structure, Hc and Hb are adjacent (ortho), so J(Hc–Hb) is larger than J(Ha–Hc) (meta).

Hello! I have a few questions related to NMR that I would love clarification on, thank you so much!



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Ha and Hb are vinylic hydrogens across a C=C double bond, and from the drawing they are trans to each other.
trans (H–C=C–H) → 11–18 Hz

cis → 5–10 Hz

geminal (same carbon) → 0–3 Hz

Quote from: amimi on February 17, 2026, 12:46:38 AMHello! I have a few questions related to NMR that I would love clarification on, thank you so much!

   

Q 13 -The arrow points to a vinylic carbon (terminal alkene CH₂).
Vinylic hydrogens typically appear around 4.6–6.5 ppm, and a terminal alkene =CH₂ is commonly near 4.8–5.0 ppm.
So 4.82 ppm is the best match.
Q 14-The arrow points to the CH₂ attached to –OH (an alcohol carbon, –CH₂OH), which is deshielded by oxygen and usually appears around 3.3–4.0 ppm.
So 3.50 ppm is the correct value.