D(NH3) по O2=Mr(NH3)/Mr(O2)=14+1*3/2*16=17/32=0,53125
FeCl3<span> + 3 </span>NaOH<span> = Fe(OH)3 ↓+ 3 NaCl
</span><span>3H2SO4 + 2Fe(OH)3 = Fe2(SO4)3 + 6H2O
</span><span>Cu(OH)2 + 2NaOH = Na2CuO2 + 2H2O
</span><span>Al2(SO4)3 + 6NaOH = 2Al(OH)3 + 3Na2SO4
</span><span>2 Al(OH)3 + 3 H2SO4 = Al2(SO4)3 + 6 H2O
</span><span>Al(OH)3 + NaOH = NaAlO2 + 2H2O</span>
<span>ОТВЕТ-Б.
PH3, у P степень окисления -3</span>