Why is sodium hypochlorite basic?

Answer 1

Na+ ion has no ability to hydrolyze water, but ClO- ion can.

That is,

Na+ + H2O -> N.R.

ClO- + H2O <=> HClO + OH- (this reaction is increasing alkalinity of solution)

To put it another way:

The first reaction, were it to occur to some appreciable extent, would be producing NaOH, a known strong base. We call it a strong base because it completely dissociates in solution. So, the equilibrium of that reaction,

Na+ + H2O <=> NaOH + H+

is extremely, extremely reactant-favored, so much so that we say that Na+ has no capacity to bond with OH- while in solution.

Answer 2

Sodium hypochlorite is basic because it undergoes hydrolysis in water to produce hypochlorous acid and hydroxide ions. The presence of hydroxide ions in solution increases the pH, making it basic.