$
Fe+2HCl→FeCl_{2}+H_{2}
FeS+HCl→FeCl_{2}+H_{2}S
Pb(NO_{3})_{2}+H_{2}S→PbS+2HNO_{3}.
n_{PbS}=23,9239=0,1mol=n_{H_2S}
=> V_{H_2S}=0,1.22,4=2,24l
n_Y=0,11mol=> n_{H_2}=0,01mol
=> V_{H_2}=0,01.22,4=0,224l
n_Fe=nH2=0,01mol
n_FeS=nH2S=0,1mol
=> m = m_Fe + m _{H_2S}=9,36g$