Step1. Write the half-reaction for the oxidation of dichloroaceticacid
"CHCl"_2"COOH" +2"H"_2"O" → "2CO"_2 + "Cl"_2 +"6H"^"+" + "6e"^"-"CHCl2COOH+2H2O→2CO2+Cl2+6H++6e-
Step 2. Calculate the amount of dichloroacetic acid
Six electrons are transferred in the half-reaction, so
"1 eq" = 1/6 "mol"1 eq=16mol
1.2 color(red)(cancel(color(black)("eq"))) × (1/6 "mol")/(1 color(red)(cancel(color(black)("eq")))) = "0.20 mol"
Step 3. Calculate the molecules of "NH"_3 neutralized
"CHCl"_2"COOH" + "NH"_3 → "CHCl"_2"COO"^"-"color(white)(l) "NH"_4^"+"
"Molecules of NH"_3
= 0.20 color(red)(cancel(color(black)("mol CHCl"_2"COOH"))) × (1 color(red)(cancel(color(black)("mol NH"_3))))/(1 color(red)(cancel(color(black)("mol CHCl"_2"COOH")))) × (6.022 ×10^23 "molecules NH"_3)/(1 color(red)(cancel(color(black)("mol NH"_3)))) = 1.2 × 10^23 color(white)(l)"molecules NH"_3