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

What is the number of moles of solute dissolved in $1 \ L$ of solution called?

$(a)$ If we take hydrochloric acid and acetic acid of the same concentration,which one will produce a lower $H^{+}$ ion concentration? Out of the two,which one is a weak acid?
$(b)$ If someone is suffering from acidity,which of the following would you suggest to cure it: vinegar,orange juice,or baking soda solution? Give a reason for your answer.

What effect does dihydrogen gas $(H_2)$ have on litmus paper?

What happens when a solution of an acid is mixed with a solution of a base in a test tube?
$(i)$ The temperature of the solution increases
$(ii)$ The temperature of the solution decreases
$(iii)$ The temperature of the solution remains the same
$(iv)$ Salt formation takes place

Answer the following:
$(i)$ Why is Plaster of Paris written as $CaSO_{4} \cdot 1/2 H_{2}O$? How is it possible to have half a water molecule attached to $CaSO_{4}$?
$(ii)$ Why is sodium hydrogen carbonate an essential ingredient in antacids?
$(iii)$ When electricity is passed through an aqueous solution of sodium chloride,three products are obtained. Why is the process called chlor-alkali?