Question

What is redid reaction?Give an example,why is the melting point of ice formed from tap water is below 0 degree celcius?

Answer 1

do you mean redox reaction?!

An oxidation-reduction (redox) reaction is a type of chemical reaction that involves a transfer of electrons between two species. An oxidation-reduction reaction is any chemical reaction in which the oxidation number of a molecule, atom, or ion changes by gaining or losing an electron.
example:

2H2 + O2 <--> 2 H2O

Diatomic hydrogen (H2), with an oxidation state of 0, combines with diatomic oxygen (O2), also with an oxidation state of 0, to form water (H2O).

When this happens, each hydrogen gives up a single electron (is oxidized), and each oxygen gains two electrons (is reduced).

Under normal conditions, ordinary fresh water freezes and melts at 0°C, or 32°F. If water and ice are at 0°C, which is the melting point of ice and the freezing point of water then molecules of ice are escaping into the water (melting), and molecules of water are being captured on the surface of the ice (freezing)