Sodium hydrogencarbonate when added to acetic acid evolves a gas. Which of the following statements are true about the gas evolved?
$(i)$ It turns lime water milky
$(ii)$ It extinguishes a burning splinter
$(iii)$ It dissolves in a solution of sodium hydroxide
$(iv)$ It has a pungent odour

The metal salt $A$ is blue in colour. When salt $A$ is heated strongly over a burner,a substance $B$ present in it is eliminated and a white powder $C$ is left behind. When a few drops of a liquid $D$ are added to powder $C$,it becomes blue again.
$(a)$ Identify $A, B, C, D$.
$(b)$ Write the chemical equations involved.
$(c)$ Give an example of a salt which also shows the above property.

Give three practical applications of neutralisation reaction.

What happens when metal oxide reacts with water?

Tap water conducts electricity,whereas distilled water does not. Why?

Write the chemical name and formula of the following:
$(a)$ Salt formed by the combination of a weak acid like carbonic acid and a strong base like sodium hydroxide.
$(b)$ Basic substance formed by the chlor-alkali process.
$(c)$ Substance added to cakes to make them fluffy.