Spot the odd one out

Exercise and reference answers

Questions

1. Items

   1. H2
   2. O2
   3. HCl
   4. Cl2

   Odd item

   HCl

2. Items

   1. CO2
   2. H2O
   3. N2
   4. HCl

   Odd item

   N2

3. Items

   1. mono-
   2. di-
   3. tri-
   4. Dalton

   Odd item

   Dalton

Instructions

Tap the one that does not belong with the rest.

Explanation