NCERT Section

Why is the amount of gas collected in one of the test tubes in the electrolysis of water activity double the amount collected in the other? Name this gas.

Give an example of a double displacement reaction.

What is a balanced chemical equation? Why should chemical equations be balanced?

Balance the following chemical equation:

$\mathrm{NaOH}+{\mathrm{H}}_2{\mathrm{SO}}_4\to {\mathrm{Na}}_2{\mathrm{SO}}_4+{\mathrm{H}}_2\mathrm{O}$

Write the balanced chemical equation for the following word equation: 

 Zinc $+$ Silver nitrate $\to$ Zinc nitrate $+$ Silver.

Write the balanced chemical equation for the following word equation: 

Aluminium $+$ Copper chloride $\to$ Aluminium chloride $+$ Copper.

Why are decomposition reactions called the opposite of combination reactions? Write equations for these reactions.

Write one equation each for decomposition reactions where energy is supplied in the form of heat, light and electricity.