Chlorobenzene (0.100 mol) is mononitrated with 80 percent total yield, and the nitro products are 70 mol percent para and 30 mol percent ortho (negligible meta). Atomic masses: H = 1, C = 12, N = 14, O = 16, Cl = 35.5. The mass of 1-chloro-4-nitrobenzene obtained is

Answer: A

Molar mass of

C X_{6} H X_{4} ClNO X_{2}

72 + 4 + 35.5 + 14 + 32 = 157.5

. Total product =

0.100 \times 0.80 = 0.0800

mol; para fraction =

0.0800 \times 0.70 = 0.0560

mol; mass =

0.0560 \times 157.5 = 8.82

g. The other options correspond to ignoring the yield, using the ortho fraction, or using the total yield.