PTHH :
\(2Na+2H_2O-->2NaOH+H_2\)
0,2__________________0,1
\(2NaOH+2AgNO_3-->2NaNO_3+Ag_2O+H_2O\)
0,03______________________________0,015
\(n_{Na}=\dfrac{5,1}{23}=0,2\left(mol\right)\)
\(n_{AgNO_3}=\dfrac{5,1}{170}=0,03\left(mol\right)\)
=>Na dư =>\(n_{NaOH}dư=0,1-0,03=0,07\left(mol\right)\)
=> \(m_{Ag_2O}=0,015.232=3,48\left(g\right)\)