$n_{Cu(OH)_2}=\dfrac{7,35}{98}=0,075(mol)$
$2C_3H_8O_3+Cu(OH)_2\to (C_3H_7O_3)_2Cu+2H_2O$
$\to n_{C_3H_8O_3}=0,075.2=0,15(mol)$
$n_{Na}=\dfrac{3,91}{23}=0,17(mol)$
$2CH_3OH+2Na\to 2CH_3ONa+H_2$
$C_3H_5(OH)_3+3Na\to C_3H_5(ONa)_3+\dfrac{3}{2}H_2$
Theo PTHH: $n_{CH_3OH}+3n_{C_3H_5(OH)_3}=n_{Na}$
$\to n_{CH_3OH}=0,17-0,15.3=-0,28(mol)$ (vô lí, không có đáp án)