What is the $H_{3}O^{+}$ ion called?

Which of the following substances enters our body when a red ant bites us?

$A$ student prepared solutions of $(i)$ an acid and $(ii)$ a base in two separate beakers. She forgot to label the solutions and litmus paper is not available in the laboratory. Since both the solutions are colourless,how will she distinguish between the two?

Which gas is produced when a base reacts with a metal?

Explain the action of dilute hydrochloric acid on the following with chemical equations:
$(a)$ Magnesium ribbon
$(b)$ Sodium hydroxide
$(c)$ Crushed egg shells

State the number of water molecules present in crystals of washing soda and Plaster of Paris. What are these water molecules called?