If a weak acid is 25 deprotonated at ph 4 what would the pka be

Concerning the 10.0 ml of 0.50 m nacl to 100 ml of solution: when a solution is diluted, does it change the number of moles dissolved?

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.

Type the letter that represents the correct location for each particle type below.