0,7 моль х моль
2HCOOH+Mg=(HCOO)₂Mg+H₂
2 моль 1 моль
n(HCOOH)=30:46=0,7 моль
х(H₂)=0,7*1:2=0,3 моль
V(H₂)=0,3*22,4=7,3 дм³
ответ:1
..........................................................
<span><span>4Fe</span>+<span>3<span>O2 </span></span>→ <span>2<span>Fe2O3
</span></span></span><span><span>Fe2O3</span>+<span>6<span>HCl</span></span> → <span>2<span>FeCl3</span></span>+<span>3<span>H2O </span></span></span>
<span><span>FeCl3</span>+<span>3<span>NaOH</span></span> → <span>3<span>NaCl</span></span>+<span>Fe<span>(OH)</span>3
</span></span><span><span>2<span>Fe<span>(OH)</span>3</span></span>+<span>3<span>H2SO4</span></span> → <span>Fe2<span>(SO4)</span>3</span>+<span>6<span>H2<span>O
</span></span></span></span>