Salt water symbolises the tears of slavery.
The tears of the Israelites.
salt water symbolises the tears of the israelites.
The bitter herbs on Passover symbolise the bitter taste of slavery and affliction.
Salt water
Either the leaving of Egypt, or the slavery of Egypt.
Salt Water at the Passover seder symbolizes the tears shed by the ancient Hebrew slaves.
It symbolizes the mortar used by the ancient Israelites to build.
Mei melach (מי מלח)
During the reading of the Haggadah (the story of the exodus from Egypt), we eat a number of symbolic foods. We dip a couple items into salt water, the salt water represents the tears of slavery.
You do not dip anything on Purim. You are referring to the holiday of Passover, and the vegeteble is called Karpas (כרפס)
purity, cleansing
All salt is kosher unless something is added to it to make it not kosher. Like all other seasonings, the specific package must be certified kosher for Passover.
Fresh water chestnuts are fine. Canned water chestnuts require a kosher for Passover hechsher.