given that hclo4 an aqueous solution is 4810-8 m

Question

Given that HClO₄ an aqueous solution is 4.8*10-^8 M, write the equation for the reaction of HClO₄ , compute [H3O+], [OH-], pOH and pH b. if it is given that an aqueous solution is 0.90 M of Nitric acid with Ka = 4.5*10^^-4,write equilibrium reaction for HNO₂ and compute equilibrium concentrations of all species, compute pH , OH^-, and the pOH