Question

Indicate in the row of electrolytes acids, hydroxides and salts: CdCl2, Mn(OH)2, Fe(NO3)2, H2SiO3, KOH, C2H5COOH, Ca(OH)2, HCNS, NiHPO4. Select weak electrolytes and write the equations of step dissociation and expressions of step dissociation constants. Write the general equations of dissociation and expressions of the general dissociation constants.

Answer 1

Acids - H₂SiO₃ , C₂H₅COOH , HCNS

Hydroxides -  Mn(OH)₂ , KOH, Ca(OH)₂

Salts - CdCl₂ , Fe(NO₃ )₂ , NiHPO₄

C₂H₅COOH is a weak acid.

C₂H₅COOH $\to$ C₂H₅COO^- + H⁺

Dissociation constant = $\frac{[C2H5COO^-][H^+]}{[C2H5COOH]}$ All the conc. are at taken at equilibrium.

H⁺ + C₂H₅COOH$\to$ C₂H₅COOH H+

Dissociation constant = $\frac{[C2H5COOH H^+]}{[C2H5COOH][H^+]}$All the conc. are at taken at equilibrium.

General equation : HA$\to$ H⁺ + A^_

Dissociation constant = $\frac{[H+][A^-]}{[HA]}$ All the conc. are at taken at equilibrium.