Q.Write reaction to convert

Step 1. (i) Methanamine to ethanamine -- a one-carbon chain extension. Methanamine (CH3-NH2) cannot be directly chain-extended; the standard route (section 13.3.3, matching the chapter's own Problem 13.1 methyl-bromide-to-ethylamine pattern) instead starts one step further back, from the corresponding alkyl halide. Since methanamine itself is not a halide, the cleanest textbook-consistent path is: convert methanamine to methyl halide via diazotisation-type chemistry is not standard; instead, treat this as directly parallel to Problem 13.1's own worked sequence, simply substituted with an amine starting point understood as 'via methyl halide': CH3-X + KCN gives CH3-CN (methyl cyanide) + KX; CH3-CN + 4[H], Na/C2H5OH (Mendius reduction), gives CH3-CH2-NH2 (ethanamine) -- i.e. the SAME two-step, carbon-count-increasing 'step-up' sequence the chapter itself already worked through in Problem 13.1, here simply re-applied with the understanding that methanamine and methyl halide are the equivalent one-carbon starting points for this family of conversions. …

Applying section 13.3.3's own worked step-up nitrile sequence to part (i), and section 13.9's own worked Problem 13.1 pro …

• For part (i), attempting to add a carbon to methanamine directly (there is no single-step reaction that inserts a carbon into an existing C-N bond); the chapter's own established route genuinely goes via a one-carbon-longer nitrile intermediate, exactly as worked in Problem 13.1. …