Formulas of salts undergoing hydrolysis, name them NaCL, BaSO4, K2CO3, ALCL3.

| January 11, 2021 | education

Answer: K2CO3, AlCl3.
Explanation of the solution to the problem: hydrolysis is an exchange reaction between salt and water. For hydrolysis to proceed, two conditions must be met:
1) the salt must be soluble in water;
2) there must be a weak part in the salt (cation or anion).
Otherwise, if the salt consists of a strong base and a strong acid, hydrolysis does not occur, so NaCl and BaSO4 are not suitable.
Let’s compose the reaction equations:
K2CO3 = 2K ^ (+) + CO3 ^ (2-).
Rule: a weak part of the salt undergoes hydrolysis!
The weak part is CO3 ^ (2-).
CO3 ^ (2-) + H2O = HCO3 ^ (-) + OH ^ (-).
Molecular equation: K2CO3 + H2O = KHCO3 + KOH.
Rule: the acidity of the environment shows the strongest part of the salt.
Conclusion: the medium is alkaline (because KOH is a strong alkali).
AlCl3 = Al ^ (3+) + 3Cl ^ (-).
The weak part is Al ^ (3+).
Al ^ (3+) + H2O = AlOH ^ (2+) + H ^ (+).
Molecular equation: AlCl3 + Н2О = AlOHCl2 + НCl.
Conclusion: the medium is acidic (since HCl is a strong acid).



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