ICSE Class 8 Answered

Dear Student,

It is necessary to have basic theoretical knowledge about chemical reactions between different types of compounds.

For example,

1. Alkali metals react with hydracids to form hydrogen gas.

2Na + 2HCl → 2NaCl + H₂

2. Metals can directly react with lukewarm or normal water to form hydrogen gas. The reaction can be vigorous like in the case of sodium.

Ca + 2H₂O → Ca(OH)₂ + H₂

3. Meth­ane when heat­ed with wa­ter va­pors at high temperatures (1000 °C), produce hydrogen

CH₄ + Н₂О → C + 2H₂