One liter of a phosphate buffer, 0.100 m. ph 7, is required. a) how would this buffer prepared if the reagents available are sodium dihydrogen phosphate (nah2po4 x h2o) and disodium hydrogen phosphate (na2hpo4) present as solids? distilled water is also available. b) how would this buffer be prepared if the reagents available are phosphoric acid (h3po4) and 1.5 m naoh? concentrated phosphoric acid is 15 m. distilled water is also available.