What are three every day devices that could not have been developed without the discovery of electromagnetism

Is this a single replacement reaction or there is no

What is impossible to do with a hypothesis

The covalent compound acetylene, which is the fuel of the oxyacetylene torch used by welders, has the molecular formula c2h2. the covalent compound benzene, a commercial solvent, has the molecular formula c6h6 each of these covalent compounds contains carbon and hydrogen atoms in a one-to-one ratio. would it be correct to write the chemical formulas of each as ch? explain.