Question

A 3.00-mL aliquot of 0.001 M, NaSCN is diluted to 25.0 mL with 0.2 M Fe(NO3)3 and 0.1 M HNO3.

Answer 1

M1 V1 = M2 V2

0.001*3 = M2*25

M2 = 0.003/25 = 0.00012M of SCN^-

SCN^- + Fe³⁺ ------->FenCS²⁺

1 mole scn^-produces 1 mole of fencs²⁺

1 mole SCN- produces 1 mole of FeNCS2+

no of moles of FeNCS2+ = molarity * volume in L

                                   = 0.00012*0.025 = 3*10^-6 moles

molesper liter   = 3*10^-6 *1000/25 = 3*10^-4 moles/liter