How do I learn all the chemical equation by-heart?

The best way, and this has worked for me and everyone else in y school would be to keep a small notebook exclusively for equations. Divide the notebook into organic and inorganic chemistry and write doen every reaction that you see in your prescribed textbook. Make it a point to glance at this book every time you time you need help with a reactiona dn revise the formulae every day. Constantly doing this will ensure that you know all the reactions perfectly.