Zinc reacts with concentrated sulphuric acid to form zinc hydride and sulphide gas.

An endothermic reaction is indicated by writing ‘+ Heat’ in the reactant side.

Any gas evolved during a reaction is represented by an arrow pointing upwards preceding the chemical formula.

Solid state is indicated by the symbol (s).

The products are always written on the right-hand side in a chemical equation with a plus sign (+) between them.

Aqueous solution, i.e., the solution made in water is indicated by the symbol (l).

Any precipitate formed is shown by an arrow pointing downwards preceding its chemical formula.

The pressure, the temperature and the catalyst used in the reaction are also indicated in the chemical equation by writing them above or below the arrow sign.

Methane burns in air to form carbon dioxide and H2.

What is the colour of precipitate of BaSO4?

At what temperature and pressure the given reaction takes place?
N2 + 3H2 → 2NH3

Which of the following is a catalyst that accelerates the decomposition of KClO3?

Which of the following is a blue coloured solution?

The reaction between CaO + H2O forms which products?

Which of the following is a white precipitate?

Magnesium burns with a bright white light in the presence of a gas forming magnesium oxide. Which of the following is that gas?

Which of the following symbol shows that the reaction can proceed in either direction?