What is the wavelength of one ultraviolet photon if it’s frequency is 1.50 x 10^15 s^-1

Identify the limiting reactant when 9.65-g h2so4 reacts with 6.10-g of naoh.the equation is h2s04 + 2naoh = 2h2o + na2so4• what is the theoretical yield of na2so4, in grams? • how much of the excess reagent will remain after the reaction has been completed? • if 10.5-g of na2so4 are actually recovered experimentally, what is the percent yield?