Question

What happens when Washing soda is added to a beaker containing hard water.

Answer 1

Nothing special... It just acts the same. It is so bcoz the hard water also has same chemical properties as normal water.

Answer 2

When washing soda is added to a beaker containing hard water, the water becomes soft.

After adding washing soda, a scum also forms on the top of the beaker.

Hard water has an abundance of calcium ions.

When washing soda, that is, sodium carbonate is added to hard water, it reacts with the calcium ions to produce a precipitate.