Question

помогите, пожалуйста. 

Answer 1

MgCl₂ + H₂O = MgOHCl + HCl
Mg²⁺ + 2Cl⁻ + H₂O = MgOH⁺ + Cl⁻ + H⁺ + Cl⁻
H₂O + Mg²⁺ = MgOH⁺ + H⁺
MgOHCl + H₂O = Mg(OH)₂ + HCl
MgOH⁺ + Cl ⁻ + H₂O = Mg(OH)₂ + H⁺ + Cl⁻
MgOH⁺ +  H₂O = Mg(OH)₂ + H⁺ ( среда кислая)

K₂S + H₂O = KHS + KOH
2K⁺ + S²⁻ + H₂O = K⁺ + HS⁻ + K⁺ + OH⁻
S²⁻ + H₂O =  HS⁻ +  OH⁻
KHS + H₂O = KOH + H₂S
K⁺ + HS⁻ + H₂O = K⁺ + OH⁻ + H₂S
HS⁻ + H₂O = OH⁻ + H₂S ( среда основная)

Fe(NO₂)₂ + H₂O = FeOHNO₂ + HNO₂
Fe²⁺ + NO₂⁻ + H₂O = FeOH⁺ + NO₂⁻ + H⁺ + NO₂⁻
Fe²⁺ +  H₂O = FeOH⁺ + H⁺ 
FeOHNO₂ + H₂O = Fe(OH)₂ + HNO₂
FeOH⁺ + NO₂⁻ + H₂O = Fe(OH)₂ + H⁺ + NO₂⁻
FeOH⁺ +  H₂O = Fe(OH)₂ + H⁺ ( среда кислая)

Mg(NO₃)₂ + H₂O = MgOHNO₃ + HNO₂
Mg²⁺ + NO₃⁻ + H₂O = MgOH⁺ + NO₃⁻ + H⁺ + NO₃⁻
Mg²⁺ +  H₂O = MgOH⁺ + H⁺ 
MgOHNO₃ + H₂O = Mg(OH)₂ + HNO₃
MgOH⁺ + NO₂⁻ + H₂O = Mg(OH)₂ + H⁺ + NO₃⁻
MgOH⁺ +  H₂O = Mg(OH)₂ + H⁺ ( среда кислая)

ZnBr₂ + H₂O = ZnOHBr + HBr
Zn²⁺ + 2Br⁻ + H₂O = ZnOH⁺ + Br⁻ + H⁺ + Br⁻
Zn²⁺ +  H₂O = ZnOH⁺ +  H⁺
ZnOHBr + H₂O = Zn(OH)₂ + HBr
ZnOH⁺ + Br⁻ + H₂O = Zn(OH)₂ + H⁺ + Br⁻
ZnOH⁺ + H₂O = Zn(OH)₂ + H⁺ ( среда кислая)$

2CrSO₄ + 2H₂O = (CrOH)₂SO₄ + H₂SO₄
2Cr²⁺ + 2SO₄²⁻ + 2H₂O = 2CrOH⁺ + SO₄²⁻ + 2H⁺ + SO₄²⁻
2Cr²⁺ +  2H₂O = 2CrOH⁺ + 2H⁺ 
(CrOH)₂SO₄ + H₂O = Cr(OH)₂ + H₂SO₄
2CrOH⁺ + SO₄²⁻ + H₂O = Cr(OH)₂ + 2H⁺ + SO₄²⁻
2CrOH⁺  + H₂O = Cr(OH)₂ + 2H⁺ (среда кислая)

BaSO₄ + H₂O =  гидролиза нет (среда нейтральная)
2СaCO₃ + 2H₂O = Ca(HCO₃)₂ + Ca(OH)₂
2СaCO₃ + 2H₂O = Ca²⁺ + 2HCO₃⁻ + Ca²⁺ + 2OH⁻
2СaCO₃ + 2H₂O = Ca²⁺ + 2HCO₃⁻ + Ca²⁺ + 2OH⁻
Ca(HCO₃)₂ + H₂O = Ca(OH)₂ + CO₂ + H₂O
Ca²⁺ + 2HCO₃⁻ + H₂O = Ca²⁺ + 2OH⁻ + CO₂ + H₂O
2HCO₃⁻ + H₂O =  2OH⁻ + CO₂ + H₂O ( среда основная)

.