Răspuns:
a)
K2Cr2O7 + 6 KI + 7 H2SO4 → 4 K2SO4 + 3 I2 +Cr2(SO4)3 + 7 H2O
6 I-I - 6 e- → 6 I0 (oxidare) agent reducator
2 CrVI + 6 e- → 2 CrIII (reducere) agent oxidant
b)
ms=0,025kg=25g
C=60%
md=Cxms/100=60x25/100=15g KI
MKI=39+127=166g/mol
n=m/M=15/166=0,09moli KI
CM=n/Vs
Vs=nxCM=0,09x1,4=calculeaza
Explicație: