Question

Sa se egaleze redox:
a) MnO2+HCl2 - MnCl2+H2O+Cl2
b) Al+H2So4 - Al2(So4)3+H2

Answer 1

Răspuns:

a. $\bf\underline{Mn^{+4}}O_2^{-2}+H^{+1}\underline{\underline{Cl^{-1}}}\rightarrow \underline{Mn^{+2}}Cl_2^{-1}+H_2^{+1}O^{-2}+\underline{\underline{Cl_2^0}}$

$\bf Mn^{+4}\xrightarrow{+2e^-}Mn^{+2}|\cdot2\!\!\!/ \:\:1\:\:\: reducere$

$\bf 2Cl^{-1}\xrightarrow{-2e^-}Cl_2^{0}|\cdot2\!\!\!/ \:\:1\:\:\: oxidare$

Din egalarea redox nu avem coeficienți, deci vom egala algebric:

MnO₂ + 4HCl → MnCl₂ + 2H₂O + Cl₂↑

b. $\bf \underline{Al^0}+\underline{\underline{H_2^{+1}}}S^{+6}O_4^{-2} \rightarrow\underline{Al_2^{+3}}(S^{+6}O_4^{-2})_3+\underline{\underline{H_2^0}}$

$\bf Al^{0}\xrightarrow{-3e^-}Al^{+3}|\cdot2\:\:\: oxidare$

$\bf 2H^{+1}\xrightarrow{+2e^-}H_2^0|\cdot3\:\:\:reducere$

Din egalarea redox avem coeficientul 2 la aluminiu, 3 la acid sulfuric și 3 la hidrogen:

2Al + 3H₂SO₄ → Al₂(SO₄)₃ + 3H₂↑