2KClO3 -to-> 2KCl + 3O2 (1)
NaCl --đpnc--> Na +Cl2 (2)
mNaCl=25/100 .a=0,25a(g)
=>nNaCl=0,25a/58,5=0,0042a(mol)
mKClO3=a - 2,5a=0,75a(g)
=> nKClO3=0,75a/122,5=0,0061a(mol)
mchất rắn thu được=90,4/100 .a=0,904a(g)
theo (1): nKCl=nKClO3=0,0061a(mol)
=>mKCl=0,0061a.74,5=0,455a(g)
theo (2) : nNa=nNaCl=0,0042a(mol)
=>mNa=0,0042.23=0,096a(mol)
=>%mKCl =0,455a/0,904a .100=50,33(%)
%mNa=0,0966a/0,904a .100=10,68(%)