$(RCOO)_3C_3H_5+3NaOH\to 3RCOONa+C_3H_5(OH)_3$
$n_{C_3H_5(OH)_3}=\dfrac{1,84}{92}=0,02 mol$
$\Rightarrow n_{RCOONa}=0,02.3=0,06 mol$
$M_{RCOONa}=\dfrac{18,24}{0,06}=304=R+44+23$
$\Leftrightarrow R=237 (C_{17}H_{33}-)$
Vậy A là $(C_{17}H_{33}COO)_3C_3H_5$