a)
\(X : CH_2=CH_2\\ Y : CH_3-CH_2-OH\\ Z : CH_3-CH_2-COOH\)
b)
\(CH_2=CH_2 + Br_2 \to CH_2Br-CH_2Br\\ 2CH_3-CH_2-OH + 2Na \to 2CH_3-CH_2-ONa + H_2\\ 2CH_3-CH_2-COOH + 2Na \to 2CH_3-CH_2-COONa + H_2\\ 2CH_3-CH_2-COOH + CaCO_3 \to (CH_3-CH_2-COO)_2Ca +C O_2 + H_2O\)