Write true or false for the following statements:
Care must be taken while mixing concentrated nitric acid or sulphuric acid with water. The water must always be added slowly to the acid with constant stirring.

Who proposed the acid-base theory of ionization?

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?

$(a)$ 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.

Write true or false for the following statement:
The universal indicator shows the same colour at different concentrations of hydrogen ions in a solution.

Melittin present in the bite of honeybee is a polypeptide containing $......$ amino acids.