饱和一元醇的通式为CnH2n+1OH,4.6g某饱和一元醇与足量金属钠反应,得到1.12L（标准状况）的氢气.

2CnH2n+1OH + 2Na---->2CnH2n+1ONa + H2
2 1
xmol 1.12/22.4=0.05mol
x=0.1mol
M=m/n=4.6/0.1=46g/mol
12n+1*(2n+1)+17==46
n=2
所以答案B.C2H5OH