Do all elements pick up or lose valence electrons or are there exceptions?

What is the h+ concentration for an aqueous solution with poh = 4.01 at 25 ∘c? express your answer to two significant figures and include the appropriate units.

Complete this brønsted-lowry reaction placing each product by its appropriate label. hso4- + hcn

What pressure will be exerted by 0.675 moles of a gas at 25*c if it is in a 0.750-l container?