我不會解~~~有機化學的問題!!!

Question

Increased substituted around a bond leads to increased strain. Take the four substituted butanes listed below, for example. For each compound, sight along the C2-C3 bond and drew Newman projections of the most stable and least stable conformation .Use the in Table 4.1 assign strain energy values to each conformations is most strained?    Which is least strained?   （a）2-Methylbutane              （b）2,2-Dimethylbutane   （c）2,3-Dimethylbutane           （d）2,2,3-Trimethylbutane

Answer 1

取代基越多，原子團間排斥力造成化學鍵內應力越大。以C2-C3 鍵來看，2,2,3-Trimethylbutane兩個碳上各有兩個及三個甲基，因此化學鍵內應力最大，也就是most strained.
ans.: (d)

Answer 2

Where is Table 4.1??