Đáp án B
– CH3NH3OOC(CH2)4COOH (X) + 2NaOH → NaOOC(CH2)4COONa (Y) + CH3NH2↑ + H2O.
–NaOOC(CH2)4COONa(Y)+H2SO4→ HOOC(CH2)4COOH (Z) + Na2SO4.
– nHOOC(CH2)4COOH (Z) + nH2N(CH2)6NH2 (T) → xt , t ° [-OC(CH2)4COHN(CH2)6NH-]n + 2nH2O.
||⇒ MX = 177 g/mol