`n_{KMnO_4}={15,8}/{158}=0,1(mol)`
`2KMnO_4+16HCl->2KCl+2MnCl_2+5Cl_2+8H_2O`
`n_{Cl_2}=5/2n_{KMnO_4}=0,25(mol)`
`n_{NaOH}=0,5.1,5=0,75(mol)`
`Cl_2+2NaOH->NaCl+NaClO+H_2O`
Do `0,25<{0,75}/2->NaOH` dư `0,75-0,25.2=0,25(mol)`
`n_{NaCl}=n_{NaClO}=n_{Cl_2}=0,25(mol)`
`->C_{M\ NaCl}=C_{M\ NaClO}=C_{M\ NaOH(du)}={0,25}/{0,5}=0,5M`