JEE Main levelSingle correct optionDifficulty 2 of 3hx194
The mass percentage of chlorine in DDT, CX14HX9ClX5 (atomic masses: C 12, H 1, Cl 35.5), is closest to
A50.1 %
B40.1 %
C30.0 %
D44.5 %
Answer: A
Molar mass =14(12)+9(1)+5(35.5)=354.5gmol−1. Chlorine mass =5×35.5=177.5. Percentage =177.5/354.5×100=50.1%. The other options use 4 or 3 Cl atoms or a wrong molar mass.