Question

What is universal indicators name the chemical equation involved in the preparation of sodium hydroxide name the process

Answer 1

A mixture of dyes that changes colour gradually over a range of pH and is used (especially as indicator paper) in testing for acids and alkalis.

Common salt = NaCl [ sodium chloride]

Aqueous solution of NaCl is called - brine.

Electrolysis of brine , leads to the formation of sodium hydroxide (NaOH)

             electricity

NaCl ----------------> NaOH + H₂ + Cl₂

Here , in the electrolysis of brine , sodium hydroxide [ alkali , that is water soluble base] and chlorine gas is formed.

Hence this process is known as chlor-alkali process.

Answer 2

substance that changes its color according to while touched with an acid or a base is called universal indicator.

equation is Na+(OH) gives NaOH

the process is called castner kellner method.