Write the chemical name and chemical formula of washing soda.

$(a)$ Identify the acid and the base whose combination forms the common salt that you use in your food. Write its formula and chemical name of this salt. Name the source from where it is obtained.
$(b)$ What is rock salt? Mention its colour and the reason due to which it has this colour.
$(c)$ What happens when electricity is passed through brine? Write the chemical equation for it.

How does chloride of lime differ chemically from calcium chloride?

How do metal carbonates and metal hydrogen carbonates react with acids? Give their chemical equations. Name the gas evolved during the reaction. What will happen when this gas is passed through lime water?

Equal volumes of hydrochloric acid and sodium hydroxide solutions of the same concentration are mixed. The $pH$ of the resulting solution is checked with a $pH$ paper. What would be the colour obtained? (You may use the colour guide given in the figure.)

If $1$ mole of salt is dissolved in $2$ liters of salt solution,what is the concentration of the solution (in $;M$)?