a) CuSO4 +2KOH --> Cu(OH)2 + K2SO4 (1)
Cu(OH)2 -to-> CuO +H2O (2)
nCuSO4=0,2(mol)
theo (1,2) : nK2SO4=nCu(OH)2=nCuO=nCuSO4=0,2(mol)
=>mX=mCuO=16(g)
b) mdd sau pư =32+200-0,2.98=212,4(g)
C%dd K2SO4=\(\dfrac{0,2.174}{212,4}.100=16,4\left(\%\right)\)