A sample of a commercial fertilizer is dissolved in water and titrated with

CHEMISTRY · Multi-part · A Level · Chemistry · Amount of substance · Amount of substance

Problem

0.875\,\text{g}

sample of a commercial fertilizer is dissolved in water and titrated with

0.200\,\text{M}

NaOH(aq)

. The titration requires

35.60\,\text{mL}

of the base to reach the stoichiometric point. The only acid-reactive component in the fertilizer is assumed to be ammonium dihydrogen phosphate,

NH_4H_2PO_4

. No other acid–base reactions occur. (a) Write the balanced molecular equation for the complete neutralization of

NH_4H_2PO_4

with aqueous sodium hydroxide. (b) Calculate the number of moles of

NaOH

delivered from the buret. (c) Determine the mass of

NH_4H_2PO_4

that reacted. (d) Calculate the percent by mass of

NH_4H_2PO_4

in the fertilizer sample.