Question

how hydrolysis of Na2CO3 occur

Answer 1

In wa­ter, sodi­um car­bon­ate will hy­drolyze, caus­ing the neu­tral medi­um to be­come al­ka­line. In the pres­ence of al­ka­lis, hy­drol­y­sis of sodi­um car­bon­ate is sup­pressed, but in an acid medi­um hy­drox­ide ions bond, and an al­ka­li re­ac­tion of the medi­um takes place. The equa­tion of hy­drol­y­sis (in ion­ic form):

CO₃²⁻ + H₂O ↔ HCO₃⁻ + OH− hy­drol­y­sis of sodi­um car­bon­ate Na₂­CO₃

Equa­tion of the hy­drol­y­sis of sodi­um car­bon­ate in two de­grees:

Na₂­CO₃ + HOH ↔ NaOH + NaH­CO₃

2Na⁺ + CO₃²⁻ + HOH ↔ Na⁺ + OH⁻ + Na⁺ + HCO₃⁻

Here sodi­um runs out, leav­ing:

CO₃²⁻ + HOH ↔ OH⁻ + HCO₃⁻

Sec­ond de­gree:

Na⁺HCO₃⁻ + HOH ↔ NaOH + H₂­CO₃

Na⁺ + HCO₃⁻ + HOH ↔ Na⁺ + OH⁻ + H₂­CO₃ — sodi­um runs out, leav­ing:

HCO₃⁻ + HOH ↔ OH⁻ + H₂­CO₃, in its turn H₂­CO₃ breaks down into СО₂ and Н₂О.

Answer 2

When sodium carbonate dissolves in water it dissociates into two sodium (Na+) ions and a carbonate (CO3–2) ion;-

Na2CO3 (s) —-> 2 Na+(aq) + CO3–2(aq)

The carbonate ion is able to remove protons (H+) from water to form bicarbonate ions and hydroxide ions. Hence it is the conjugate base of the bicarbonate ion;

CO3–2(aq) + H2O(l) ←-> HCO3-(aq) + OH-(aq)

The overall increase in OH- ions due to these reactions results in an increase in the pH of the solution, and cause it to become alkaline.