To determine which alkane cannot be made in good yield by the Wurtz reaction, we need to understand the reaction mechanism.$\\$The Wurtz reaction involves the coupling of two alkyl halides in the presence of sodium metal to form a higher alkane.$\\$The general reaction is:$\\ 2 \,$R-X$+ 2 \,$Na$\rightarrow$R-R$+ 2 \,$NaX$\\$This reaction is best suited for the formation of symmetrical alkanes, as it involves the coupling of identical alkyl groups.$\\$Let's analyze each option:$\\$• Option 1: 2,3-Dimethylbutane$\\$This alkane can be formed by coupling two 2-chloropropane molecules:$\\$2 (CH$_3$-CHCl-CH$_3$) + 2 Na$\rightarrow$(CH$_3$-CH(CH$_3$)-CH(CH$_3$)-CH$_3$) + 2 NaCl$\\$This is a symmetrical coupling, so it can be formed in good yield.$\\$• Option 2: n-Heptane$\\$To form n-heptane, we would need to couple a 1-chlorobutane and a 1-chloropropane:$\\$CH$_3$-CH$_2$-CH$_2$-CH$_2$-Cl + CH$_3$-CH$_2$-CH$_2$-Cl + 2 Na$\rightarrow$CH$_3$-CH$_2$-CH$_2$-CH$_2$-CH$_2$-CH$_2$-CH$_3$ + 2 NaCl$\\$This is an unsymmetrical coupling, which often leads to a mixture of products, resulting in poor yield.$\\$• Option 3: n-Butane$\\$This alkane can be formed by coupling two 1-chloropropane molecules:$\\$2 (CH$_3$-CH$_2$-Cl) + 2 Na$\rightarrow$CH$_3$-CH$_2$-CH$_2$-CH$_3$ + 2 NaCl$\\$This is a symmetrical coupling, so it can be formed in good yield.$\\$• Option 4: n-Hexane$\\$This alkane can be formed by coupling two 1-chlorobutane molecules:$\\$2 (CH$_3$-CH$_2$-CH$_2$-Cl) + 2 Na$\rightarrow$CH$_3$-CH$_2$-CH$_2$-CH$_2$-CH$_2$-CH$_3$ + 2 NaCl$\\$This is a symmetrical coupling, so it can be formed in good yield.$\\$Therefore, the alkane that cannot be made in good yield by the Wurtz reaction is n-heptane, corresponding to Option 2.