HCHO→H2OCH3CH2MgBrA→PCCB; Functional isomer of ‘B’ is

HCHO→CH3CH2MgBrCH3CH2CH2OMgBr→H2OCH3CH2CH2OH+MgOHBr; PCC is useful in controlled oxidation; 10 alcohols on controlled oxidation give aldehydes; CH3CH2CH2OH→PCCCH3CH2CHO; Functional isomer of CH3CH2 CHO is CH3COCH3;